Noi Dung Giao Trinh Hptdinh Tinh Duoc Trung 2012

7/24/2019 Noi Dung Giao Trinh Hptdinh Tinh Duoc Trung 2012

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PHN I

L THUYT HA PHNTCH NH TNH


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BI 1

I CNG V HA HC PHN TCH NH TNH

Mc tiu

1. Trnh by uc cc phng php phn tch nh tnh.

2. Cc phn ng dung trong ha phn tch nh tnh.

3. Nu uc cc hthng phn tch caiton v anion.

Nhim vca phn tch nh tnh l xc nh cc nguyn t, cc ion, cc phn

tc trong thnh phn cht phn tch. Trong phm vi bi ny chgii thiuphn phn tch nh tnh cc ion v c trong dung dch.

1.CC PHNG PHP PHN TCH NH TNH

1.1.Phng php ha hc

L phng php nh tnh da trn cc phn ng ha hc. Phng php

ny khng cn trang thit b phc tp nn c s dng rng ri trong thc t.

Tuy nhin n khng pht hin c nhng lng cht tng i nh.

1.2.

Phng php vt l v ha l

L nhng phng php da trn cc tnh cht vt l v ha l ca cht cn

phn tch:

Phng php so mu ngn la: t cc hp cht d bay hi ca cc

nguyn t trn ngn la n gas khng mu ri quan st. V d: ngn la Na+

c mu vng, K+ c mu tm, Ba2+ c mu xanh lc nht.

Phng php dng c: l phng php dng my thit b hot ng theo

nhng nguyn l xc nh phn tch nh tnh. V d: quang ph hp th, sc

k,


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Phng php vt l v ha l c c nhy v chnh xc cao nhng

i hi trang thit b phc tp khng phi tt c c s u trang b c nn

phng php ha hc vn ng vai tr quan trng trong cng tc phn tch.

1.3.

Phn tch t v phn tch kh1.3.1.

Phn tch t

Cc phn ng dng trong phn tch nh tnh thng c tin hnh trong

dung dch. u tin ngi ta ha tan cht phn tch trong dung mi sau

cho dung dch tc dng vi thuc ththch hp.

V d: pht hin ion clorid, ngi ta ha tan mt lng NaCl trong nc,

sau nhthuc thl AgNO3vo.

1.3.2.

Phn tch kh

Cht kho st v thuc th u l dng rn.

un nng nhit cao

V d:mui Natri t ln trn ming platin nung di ngn la khng mu th

n chuyn sang mu vng; tng tmui Kali cho mu tm xanh; Strontium

cho mu cam; Barium cho mu xanh l.

Kt hp nhit v ha cht

V d:to ht mu ca Natri tetraborat (Na2B4O7, 10H2O) hay Natri

hydrophosphat ammonium (NaNH4HPO4.4H2O) bng cch kim chy (un

vi Na2CO3v KNO3).

Nghin cht rn vi thuc thrn. (do Flavitski ngh1898)

V d:nghin vi tinh thCobalt Sulfat trn bn bng svi 1 lng

Ammonium thiocyanat rn (NH4CNS) to phc (NH4)2[Co(CNS)4] c mu

xanh dng.CoSO4+ NH4SCN (NH4)2[Co(SCN)4] + (NH4)SO4.


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1.4.

Phn tch lng ln, bn vi, vi lng, siu vi lng

1.4.1.

Phn tch th:lng cht 0,1-1g hay 10-100 ml dung dch. Tin hnh

trong ng nghim , becher, bnh cu.

1.4.2.

Bn vi phn tch:0,01 0,1g cht rn hay 0,1 - 0,3 ml dung dch.1.4.3.Phn tch nh:(vi phn tch) vi mg cht rn hay 0,01 0,1 ml dung

dch.

1.4.4.Siu vi phn tch:lng cht phn tch rt nh (hng g). Thc hnh

di knh hin vi.

1.4.5. Phng php vi tinh th:thc hin trn gi mang thy tinh, quan st

ion hay nguyn t qua knh hin vi dng kt tinh.

1.4.6.Phn tch dng phn ng chuyn mu dung dch hay thu ta mu

Tin hnh trn giy v phn hy t t theo th t xc nh ca dung dch

kho st v thuc th. C th thc hin trn a s, mt knh ng h hay

chn s.

1.5.

Phn tch ring bit v phn tch h thng

1.5.1.

Phn tch ring bit

L xc nh trc tip mt ion no trong hn hp nhiu ion bng mtphn ng c hiu (phn ng ch xy ra i vi ring mt ion). C th ly

tng phn ring dung dch phn tch th ring tng ion, khng cn theo

mt th t nht nh no.

V d:tm Bi3+bng thuc th thioure c mu vng ti, Fe3+vi KSCN c

mu mu c trng.

Trong nhiu trng hp khng s dng c phng php phn tch

ring bit v khng phi tt c cc ion u c phn ng tht c hiu.1.5.2.

Phn tch h thng

L tin hnh xc nh cc ion theo mt thtnht nh. Mun phn tch

hthng mt hn hp nhiu ion, ngi ta thng dng cc thuc th nhm


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chia cc ion thnh nhiu nhm, mi nhm c thli c chia thnh cc phn

nhm v cui cng c tch ring thnh ion ring bit xc nh.

C hai hthng phn tch cation:

Hthng dng H2S. Hthng dng acid base.

2.CC PHN NG DNG TRONG PHN TCH NH TNH

2.1.Cc loi phn ng

2.1.1. Phn loi theo bn cht ha hc

Phn ng ha tan. V d:

CaCl2/nc = Ca2++ 2Cl-

CaCO3+ 2HCL = CaCl2+ CO2+ H2O

Phn ngkt ta. V d:

Ag++ Cl-= AgCl

Phn ng trung ha. V d:

Ba(OH)2+ 2HCL = BaCl2+2H2O

Phn ng to cht bay hi. V d:

NH4NO

3+ NaOH = NH

3+ NaNO

3+ H

2O

Phn ng oxy ha kh. V d:

2Mn2++ 5PbO2+ 4H+= 2MnO4+ 5Pb

2++ 2H2O

Phn ng to phc. V d:

Hg2++ 4I-= [HgI4]2-

2.1.2. Phn loi theo mc ch phn tch

Phn ng tch:

Nhm chia cc cht, cc ion thnh tng nhm nh, hay tch ring mt ion,mt cht dung cho phn ng xc nh.

Phn ng c trng hay xc nh nh:

Phn ng kha hay loi b ion cn tr.


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Phn ng m kha hoc ph phc gii phng ion cn tm.

Phn ng iu chnh pH mi trng ha tan, kt ta hoc trung ha

cht cn phn tch.

2.2.

nhy v tnh c hiu ca phn ngCc phn ng dng trong phn tch nh tnh cn phi nhanh, nhy, c

hiu, c du hiu d nhn bit nh kt ta, to mu, mu thayi trong cc

dung mi, hay cc iu kin phn ng, sinh kh c c im ring.), xy ra

hon ton. Tuy nhin, ty theo mc ch phn tch ch cn t mt vi yu cu

c th, khng nht thit phi c cc c tnh nu. Chng hn, khi tch

ring mt ion bng cch kt ta th phn ng phi hon ton. Nhng ch nh

tnh ion th khng cn phi nh vy.

Hai yu cu quan trng i vi mt phn ng nh tnh l nhy, c

hiu

2.2.1. nhy ca phn ng

L lng cht ti thiu c thpht hin bng phn ng trong iu kin

xc nh

C 2 cch biu th nhy:

nhy tuyt i hay gii hn pht hin: l lng cht nhnht, thng

tnh bng microgam ( 1mcg = 10-6g ) trong mu em thcn c pht

hin bng mt phn ng no .

nhy tng i: l nng gii hn (hay pha long gii hn ),

thng tnh theo gam/ml, cn c pht hin bng mt phn ng trong

iu kin xc nh

VD: phn ng kt ta xc nh Na+

bng thuc thStreng trong ng nghimc nhy tuyt i l 10 mcg, ngha l phi c ti thiu 10 mcg Na+trong

mu em th. Mt khc quan st c r rng trong ng nghim th th


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tch dung dch em tht nht l 0,5 ml. V vy nhy tng i bng 2 x

10-5g (Na+)/ml.

Cng phn ng nhng m thc hin bng cch soi tinh th di tnh hin

vi th thtch dung dch mu thchcn 0,001 ml, theo nhy tng ivn l 2x10-5g/ml (hay pha long l 1/50.000 so vi n vnng g/ml),

nhng nhy tuyt i sl 0,02 mcg (nhy hn 500 ln so vi phn ng

trong ng nghim).

V d trn y cho thy, nhy phthuc cch thc hin phn ng. Ngoi ra

nhy phthuc cc yu tnhit , nng , thuc th, sc mt ca cc

ion l

C mt s cch tng nhy phn ng. Chng hn, dung dch iod rt long

trong nc c mu vng kh nhn bit, nhng khi chit iod vo Cloroform

mu tm xut hin r rng.

2.2.2. Tnh c hiu ca phn ng

L trong nhng iu kin xc nh , c th dng phn ng (hay thuc th)

xc nh mt cht khi c mt cc cht khc. Tnh c hiu ca mt phn

ng c th biu th bng gi tr.

lng ion cn pht hin

F= -----------------------------

Lng ion l cng c mt

Tt nhin, F cng nh, phn ng cng c hiu.

V d: KI l thuc th dc hiu ca ion Hg2+

v n cho ta mu son HgI2rtd nhn ra, d nng Hg2+rt nh nm ln trong nhiu ion khc. Hn

na mu d dng bin mt nu cho d KI do to thnh phc [HgI4]2-tan v

khng mu.


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2.3.

Thuc th trong cc phn ng nh tnh

Yu cu ca thuc th trong phn tch: Phi tinh khit, nhy v c hiu.

tinh khit l yu cu quan trng nht, cc thuc th ha hc xp theo

tinh khit tng dn nh sau: Loi k thut thng lm nguyn liu ban u.

Loi tinh khit th nghim ha hc ni chung.

Loi tinh khit phn tch.

Loi tinh khit ha hc lm cht chun.

Loi tinh khit quang hc dng trong phn tch quang ph.

Thuc th theo tc dng phn tch: gm hai loi

Thuc th nhm: L thuc th c tc dng ging nhau ln mt nhm cc

ion. V d, HCl l thuc th ca nhm Ag+, Pb2+, Hg22+.

Thuc th chn lc: l thuc th c tc dng ging nhau trn mt s ion

m cc ion ny c th thuc cc nhm phn tch khc nhau. Chng hn,

NH3c th to phc tan v khng mu vi mt s ion nhiu nhm phn

tch.

Thuc th c hiu hay thuc th ring: l thuc th ch cho phn ng c

hiu vi mt ion hoc vi mt cht. V d: h tinh bt cho mu xanh ch

vi iod, dimethyglyoxim trong mi trng amoniac to thnh ch vi ion

Ni2+mt kt ta mu hng.

3.

PHN TCH NH TNH CATION THEO PHNG PHP ACID

BASE

C 2 ng li ch yu phn tch h thng cc cation l ng li theo

phng php dng H2S v ng li theo phng php acid base.3.1.H thng dng H2S

Nguyn tc:to ta vi cc thuc th nh : HCl, H2S, (NH4)2S/ NaOH,

(NH4)2CO3


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Cc cation c chia thnh 5 nhm ty theo thuc thchung ca nhm.

u im:kh cht ch, kt qukh chnh xc, pht hin trit cc cation.

Nhc im:H2S rt c, mi kh chu, hay gp dung dch keo ca S.

3.2.

H thng dng acid - baseNguyn tc: Cc cation to ta hay to phc vi cc acid HCl, H2SO4 hoc

vi cc base nh NaOH, NH4OH.

u im:

t c hi hn hthng dng H2S

Sdng c nhng tnh cht c bn ca cc nguyn t: quan hca cc

nguyn tny vi cc acid v base, tnh lng tnh ca cc hydroxyd v

kh nng to phc ca cc nguyn t.

Thi gian thc hin phn tch ngn hn t30 40% so vi hthng H2S

Nhc im:Phn chia nhm khng cht chbng hthng dng H2S

Phn nhm cc cation

Nhm Ion Thuc th Kt qu

I Ag+, Pb2+, Hg22+ HCl 6M Ta clorid

II Ba

2+

, Ca

2+

H2SO43M/ cn 90

o

Ta sulfat

III Al3+, Zn2+ NaOH dHydroxyd tan/ kim

d

IV Bi3+, Fe3+, Mg2+NaOH, NH4OH

+ H2O2

Hydroxyd khng tan/

kim d

V Cu2+, Hg2+ NH4OH Phc tan/ NH4OH d

VI Na+, K+, NH4+ Chuyn bit

4.

PHN TCH NH TNH ANIONDo khng c thuc thnhm r rng nn cng khng thphn chia mt cch

cht chton bcc anion thnh nhng nhm ring phn tch hthng


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ging nh cc cation. Da theo tc dng thuc thnhm anion c th c phn

loi theo bng 1.1.

Phn nhm cc anion

C ba phng php: phn tch hthng, na hthng v ring bit.

Bng1.1.Phn loi thuc th theo nhm anion

Nhm Ion

I Cl-, Br-, I-, S2-, NO3-

II PO43-, HCO3-, CO3

2-, AsO33-, AsO4

3-

III SO42-, SO3

-


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TT Thuc thnhm Nhm anion Sn phm hoc du hiu phn

ng

1

HCl 2N hay

H2SO4

CO32-; CN-; S2-;SO3

S2O32-; NO2

-; ClO-

To cc kh tng ng:

CO2(khng mu, lm c nc

vi trong); HCN(mi hnh

nhn); H2S(mi thi); SO2(mi

sc mnh); SO2v S; NO v

NO2(mu nu , kh th); Cl2

(mu vng lc, kh th)

2

BaCl2+ CaCl2trong mi trng

trung tnh

AsO33-; AsO4

3-; CrO42-;

ClO

-

; MnO4-

; SO42-

;PO4

3-; BrO3-; IO3

-; F-

To kt ta tng ng:

Ca3(AsO3)2trng; Ca3(AsO4)2trng; BaCrO4vng; Ba(MnO4)2

; BaSO4trng; Ca3(PO4)2

trng; Ba(BrO3)2trng; Ba(IO3)2

trng; CaF2trng:

3

AgNO3+ HNO3

2N

SCN-;Cl-; Br-; I- To kt ta tng ng:

AgSCN trng; AgCl trng; AgBr

vng nht; AgI vng r4 Hn hp Mg

(NH4OH +

NH4Cl + Mg Cl2)

AsO43-; PO4

3- To kt ta tng ng:

MgNH4AsO4trng; MgNH4PO4

trng.

5

KI + H2SO42N

CrO42-; AsO3

3-; MnO4-;

ClO-; ClO3-; BrO3

-;

IO3-; NO2

-

Gii phng I2

(Nhn bit iod bng mu trong

dung dch nc hoc trong

cloroform, hoc thbng htinh

bt).

6 Dung dch I2 S2-; SO3

2-; S2O32-; Lm mt mu I2


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AsO33-

7 Dung dch

KMnO4+ H2SO4

2N

S2-; SO32-; S2O3

2-;

AsO33-; NO2

-; Cl-; Br-:

I-; CN-; SCN-

Lm mt mu KMnO4

8 Khng c thuc

thnhm

NO3-; ClO4

-


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BI 2

XC NH CC CATION NHM I

(Ag+, Pb2+, Hg22+)

MC TIU

1. Trnh by c tn, cng thc ha hc ca TT nhm, TT cation, hin tng

c trng khi cation nhm I tc dng cc TT v vit phng trnh ion

minh ha.

2. Thao tcng kthut th v xc nh cation nhm I.

1.

Thuc thnhm

1.1. Thuc thnhmCc cation nhm ny c kh nng to kt ta vi hu ht cc acid (trHNO3)

nhng ch c HCl 6N th to ta vi nhm ny m khng to ta vi cc

cation nhm khc. V th acid hydrocloric nng 6M (HCl 6M) chnh l

thuc th tch nhm cation Ag+, Pb2+, Hg22+ra khi cc cation khc.

Cc cation nhm I tc dng vi acid hydrocloric 6M to thnh cc kt ta

trng, cc kt ta ny c tnh cht khc nhau trong amoni hydroxyd (NH4OH).

1.2. Phng trnh ionAg++ HCl = AgCl+ H+

AgCl tan trong dung dch NH4OH

Pb2++ 2HCl = PbCl2+ 2H+

PbCl2khng tan trong dung dch NH4OH

Hg22++ 2HCl = Hg2Cl2+ 2H

+

Hg2Cl2ha en trong dung dch NH4OH

2.

Thuc thcation

2.1. Thuc thca ion Ag+:Vi cc dung dch ca

2.1.1. Kali cromat (K2CrO4):Ag+to ra kt ta thm.

2Ag++ K2CrO4= Ag2CrO4+ 2K+


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2.1.2. Kali iodid (KI):Ag+to kt ta vng nht.

Ag++ KI = AgI+ K+

2.1.3. Natri carbonat (Na2CO3): to ra kt ta trng, lu ha xm (do

phn hy thnh Ag2O).

2.2 Thuc thca ion Pb2+

2.2.1. Amoni sulfur [(NH4)2S] hay hydrosulfur (H2S):Pb2+ to ra kt ta

en.

Pb2++ (NH4)2S = PbS+ 2NH4+

Pb2+ + H2S = PbS+ 2H+

2.2.2. Kali cromat:Pb2+ to ra kt ta vng ti, ta ny tan trong dung dch

acid nitric, dung dch natri hydroxyd, khng tan trong acid acetic.

Pb2++ K2CrO4 = PbCrO4+ 2K+

2.2.3. Kali iodid:Pb2+ to ra kt ta vng, ta ny tan trong nc nng, khi

ngui li kt ta tinh thmu vng ng nh.

Pb2++ 2KI = PbI2+ 2K+

2.2.4. Acid sulfuric long (H2SO4 3M):Pb2+ to ra kt ta trng.

Pb2++ H2SO

4=

PbSO

4+ 2H+

2.2.5. Natri carbonat:to ra kt ta trng.

Pb2++ Na2CO3 = PbCO3+ 2Na+

2.3 Thuc thca ion Hg22+

2.3.1. Amoni hydroxyd:Hg22+to ra kt ta xm en (Hgonguyn t).

Hg22++ 2NH4OH = Hg2(OH)2+ 2NH4

+

2.3.2. Kali cromat:Hg22+ to ra kt ta mu gch.

Hg22+

+ K2CrO4= Hg2CrO4 + 2K+

2.3.3. Kali iodid:Hg2

2+ to ra kt ta mu xanh lc, nu d TT th chuyn

thnh mu en (Hgonguyn t)

Hg22++ 2KI = Hg2I2+2K

+


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Hg2I2+ 2KI = Hgo+ K2[HgI4]

2.3.4. Natri carbonat:Hg22+ to ra kt ta xm en

Hg22++ Na2CO3= Hg2CO3+2Na

+

Bng1.2. Tm tt cc phn ng c trng ca cation nhm ICationThuc th

Ag+ Pb2+ Hg22+

HCL long AgCltrng, tan

trong NH4OH d

do to phc

[Ag(NH3)2]+

PbCl2trng,tan

trong nc nng

HgCl2trng, tc

dng vi NH4OH

to Hg0+ NH2HgCl

H2SO4

long

- PbSO4trng Hg2SO4trng

NaOH hay

KOH

Ag2Oen Pb(OH)2trng, tan

trong kim d, to

PbO22-

Hg2Oen

NH4OH d To phc

[Ag(NH3)2]

+

Pb(OH)2trng [Hg2ONH2]NO3 +

Hg

0

K2CO3hay

Na2CO3

Ag2CO3trng Pb2(OH)2CO3trng Hg2CO3 = HgO +

Hg +CO2

K2CrO4 Ag2CrO4nu PbCrO4vng tan

trong kim d

HgCrO4

KI AgIvng PbI2vng tan trong

nc nng

Hg2I2vng, xanh,

nu d thuc th s

to thnh HgI42- +Hg0

H2S Ag2Sen PbSen HgSen+ Hg0


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CU HI N TP

1. Trnh by tn, cng thc ha hc ca TT nhm, hin tng c trng khication nhm I tc dng vi TT nhm v vit phng trnh ion minh ha?

2. Ktn, cng thc ha hc, hin tng c trng ca cc TT xc nh ion

Ag+, Pb2+, Hg22+v vit phng trnh ion minh ha.

3. K tn cc thuc thging nhau ca ion Ag+, Pb2+, Hg22+v hin tng

khc nhau khi cc TT tc dng vi ion Ag+, Pb2+, Hg22+?

4. Hy sdng bng kim c khng tkim tra kthut thv xc

nh cation nhm I?


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Bi 3

XC NH CATION NHM II

(Ba2+, Ca2+)

MC TIU

1. Trnh by c tn, cng thc ha hc ca TT nhm, hin tng c trng

khi cation nhm II tc dng vi TT nhm v vit phng trnh ion

minh ha.

2. K c tn, cng thc ha hc, hin tng c trng ca TT xc nh

cation Ba2+, Ca2+v vit phng trnh ion minh ha.

3. Thao tc ng k thut thcation nhm II vi cc TT ca chng v xcnh ng cation nhm I, II.

1. Thuc thnhm

1.1. Thuc th nhm

Acid sulfuric 3M (H2SO43M).

Cc cation nhm II tc dng vi TT acid sulfuric 3M to ra kt ta trng.

Trong cc phn ng ta ny ion Ba2+khng cn iu kin no, cn mun ta

ion Ca2+th phi cn mi trng aceton hoc ethanol 960. Tuy nhin nngcao Ca2+ c th to ta vi SO4

2-m khng cn mi trng aceton hoc

ethanol 960.

1.2. Phng trnh ion

Ba2++ H2SO4 = BaSO4+ 2H+

Ca2++ H2SO4 = CaSO4 + 2H+

2.

Thuc thcation

2.1. Thuc thca ionBa2+: vi cc dung dch ca

2.1.1. Kali cromat: Ba2+ to ra kt ta mu vng ti, ta ny khng tan

trong NaOH 3M v CH3COOH.

Ba2++ K2CrO4 = BaCrO4+ 2K+


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5. Hy sdng bng kim c khng tkim tra kthut thcc cation

nhm II vi cc TT ca chng v xc nh cation nhm I, II?

Thuc th Ba2+ Ca2+

H2SO43M

K2CrO4

Phn ng Voller

(NH4)2C2O4

Na2CO3


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BI 4

CATION NHM III (Al3+, Cr3+, Zn2+)

Mc tiu

1. Trnh by c tn, cng thc ha hc ca thuc th nhm, thuc th

cation, hin tng c trng khi cation nhm III tc dng vi cc nhm

thuc th v vit c cc phng trnh ion minh ha.

2. Bit cch xc nh cc ion nhm III thn hp cc cation nhm I, II, v

nhm III. V trong cc hn hp ion bt k.

1. C IM

Cc cation nhm III phn ng vi kim to kt ta hydroxyt mu trng

Al(OH)3, Cr(OH)3 v Zn(OH)2. Ta tan trong kim tha to thnh

aluminat (AlO2-), cromit (CrO2), zincat (ZnO2

2-).NaOH d l thuc thnhm

ca cation nhm III. Trong dung dch Zn2+, Al3+ khng mu, Cr3+ c mu

xanh tm. Zn2+ tn ti di 2 dng Zn2+v ZnO22- , Al3+ tn ti di dng

Al3+

hay AlO2-

, Cr3+

dng cation, kt ta Cr(OH)3 pH = 5, tan trong mitrng kim d. pH = 12,5 cho cromit mu xanh en.

2. PHN NG CHUNG

TC DNG VI KIM NATRI V KALI

Cho kt ta hydroxyd mu trng

Al3+ + 3NaOH Al(OH)3 + 3Na+

Cr3+ + 3NaOH Cr(OH)3 + 3Na+

Zn2+ + 2NaOH Zn(OH)2 + 2Na+

Cc hydroxyd c tnh lng tnh, tan trong kim thhin tnh acid.

Al(OH)3 + OH- AlO2

- + 2H2O


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Cr(OH)3 + OH- CrO2

- + 2H2O

Zn(OH)2 + OH- ZnO2- + 2H2O

V tan trong acid, trng hp ny cc hydroxyd thhin mt base.

Al(OH)3 + H+ Al3+ + 3H2O

Cr(OH)3 + H+ Cr3+ + 3H2O

Zn(OH)2 + H+ Zn2+ + 2H2O

3. PHN NG NH TNH

3.1. ION Al3+

Vi NaOH

To thnh ta keo Al(OH)3. Ta tan trong lng tha NaOH to thnhaluminat

Al3+ + 3NaOH Al(OH)3 + 3Na+

Al(OH)3 + OH- AlO2

- + 2H2O

Khi thm NH4Cl vo dung dch aluminat s xut hin ta tr li. Phn ng

ny gi l phn ng thy phn aluminat. y l phn ng c dng tch

Al3+ra khi hn hp cation nhm III.

Vi thuc thnhm Aluminon (amoni aurintricarboxylat)To mui ni phc c mu . Ty nng ca Al3+sc ta bng hay

dung dch mu . Phn ng thc hin trong mi trng acid yu pH = 4 5

vi m acetat acetic

Al3+ + aluminon + m acetat ta bng .

3.2. ION Cr3+

3.2.1.

Vi NaOH

To ta hydroxyd crom mu xanh en

Cr3+ + 3NaOH Cr(OH)3 + 3Na+

Hydroxyd crom tan trong lng tha NaOH to thnh cromit mu xanh nht


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Cr(OH)3 + NaOH NaCrO2 +

2H2O

Cromit khi un si sbthy phn cho li ta hydroxyd cromit.

3.2.2. Phn ng oxy haCr3+phn ng vi oxy gi trong mi trng kim to thnh cromat c mu vng

c trng.

2Cr3+ + 3H2O2 + 10NaOH CrO42- +

8H2O

3.2.2.

Phn ng to ngc c mu

Cr3+phn ng to ngc c mu sc khc nhau vi cc mui khc nhau nh

vi natriborat hay natrihydro phosphat to ngc c mu xanh l m, trng

hp nung chy mu cha Cr3+vi hn hp bt Na2CO3 v KNO3ngc c mu

vng.

3.3. ION Zn2+

3.3.1.Vi NaOH

Ion Zn2+phn ng vi NaOH cho ta km hydroxyd, ta tan trong kim d

to thnh zincat khng mu.

Zn2+ + 2NaOH Zn(OH)2 + 2Na+

Zn(OH)2 + 2NaOH Na2ZnO2 + 2H2O

3.3.2.Vi NH4OH

To thnh Zn(OH)2tan trong lng tha NH4OH to thnh phc [Zn(NH3)4].

Phn ng ny dng tch nhm ra khi hn hp c km trong cation nhm

III

3.3.3.

Vi thuc thM.T.A(MercuriThiocyanatAmoni)(NH4)2[Hg(SCN)4]Trong mi trng trung tnh hay acid nh, ion Zn2+ cho ta Zn[Hg(SCN)4]

mu trng. Nu thm vo dung dch Zn2+1 git Cu2+, khi cho M.T.A vo s

to thnh ta tm sim.


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Zn2+ + Cu2+ + 2[Hg(SCN)4]2- ZnCu[Hg(SCN)4]2

Mu ca ta ty thuc vo lng Cu2+thm vo.

t Cu2+ tm nht

Hi tha tm en

Tha nhiu xanh vng ca Cu2+.

CU HI N TP

1.Nu c tnh quan trng nht ca cation nhm III?

2. Vit cng thc ha hc, phn ng c trng ca cc ion , Al3+, Cr3+, Zn2+

3. So snh sging v khc nhau ca cc ion Al3+, Zn2+khi tc dng vi cc

thuc thv vit phng trnh ion minh ha?

4. So snh sging v khc nhau ca cc ion ca cc ion Al3+, Cr3+khi tc

dng vi cc thuc th v vit phng trnh ion minh ha?

5. Hon thnh cc phng trnh phn ng sau:

Al3+ + ............................ Al(OH)3 + 3Na+

Cr(OH)3+ NaOH ................. + 2H2O

Zn(OH)2+ 2NaOH ................. + 2H2O

6. Lm th no tch cc cation nhm III ra khi hn hp cc cation nhmI v II

7. Lm th no tch Al3+ra khi hn hp cation nhm III?


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BI 5

CATION NHM IV (Fe3+, Mn2+, Mg2+,Bi3+)

Mc tiu

1. Trnh by c tn, cng thc ha hc ca thuc thnhm, thuc th nh

tnh ca cc cation, hin tng c trng khi cation nhm IV tc dng vi

cc thuc th v vit c cc phng trnh ion minh ha.

2. Bit cch phn tch cc ion nhm IV thn hp cc cation nhm I, II, III

v nhm IV.

Ni dung

1.

C TNH C

A CATION NHM IV

Cc cation nhm IV tc dng vi kim cho ta hydroxyd khng tan trong

kim d.

Thuc thnhm: NaOH 3M v H2O2.

Trong dung dch cc ion khng mu trFe3+c mu vng nu

Tnh oxy ha kh. Cc cation nhm IV tham gia phn ng vi oxy ha kh.

Fe3+l cht oxy ha, bkhthnh Fe2+.

Mn2+

l cht khb oxy ha n Mn7+

c mu tm. Mg2+bkhvMg0.

Bi3+bkh n Bi0nguyn t c mu en.

2.

PHN NG CHUNG

Vi KOH, NaOH, NH4OH

Fe3 + 3OH- Fe(OH)3

Mg2+ + 2OH- Mg(OH)2

Mn2+ + 2OH- Mn(OH)2

B3+ + 3OH- Bi(OH)3

3.

PHN NG NH TNH

3.1. ION Fe3+


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3.1.1.

Vi NaOH

Cho ta mu nu, khng tan trong kim d, tan trong acid v c.

Fe3+ + 3NaOH Fe(OH)3

3.1.2.

Vi kali ferrocyanid K4[Fe(CN)6]

Trong mi trng acid Fe3+to ra kt ta keo mu xanh ph.

Fe3+ + K4[Fe(CN)6] Fe4[Fe(CN)6]3

Phn ng ny rt nhy, lng ti thiu tm thy (1 2 git): 0,05g, nng

gii hn 1: 1x106.

3.1.3.

Vi kali sulfocyanat KSCN

Fe3+ tophc mu mu. Thnh phn ca phc thay i ty theo nng

ion SCN- Fe3+ + 3KSCN Fe(SCN)3 + 3K+

3.2. ION Mn2+

3.2.1.

Vi NaOH, NH4OH

Cho kt ta Mn(OH)2trng, Mn(OH)2tan mt t trong kim d do to thnh

phc hydroxo Mn(OH)3-tan trong acid v c.

Mn2+ + 2OH- Mn(OH)2

Mn(OH)2dboxy ha trong khng kh to thnh MnO(OH)2c mu nu.3.2.2.

Phn ng oxy ha

Oxy ha Mn2+bng PbO2trong mi trng acid, to thnh Mn7+c mu tm

.

2Mn2 + 5PbO2 + 4H+ 2MnO4

- + 5Pb2++ 2H2O

3.3. ION Mg2+

3.3.1.

Vi NaOH

Ion Mg2+

cho ta trng Mg(OH)2, khng tan trong kim tha, tan trongNH4OH.

Mg2+ + 2OH- Mg(OH)2

3.3.2.Vi NH4OH


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Cho ta trng Mg(OH)2, nu c shin din ca NH4Cl th Mg(OH)2 khng

kt ta c.

3.3.3.

Phn ng vi Na2HPO4

Mg2+ to vi Na2HPO4 ta v nh hnh. Nu phn ng xy ra vi s hindin ca NH4OH NH4Cl scho ta tinh thc hnh sao ca MgNH4PO4,

6H2O

Mg2+ + NH4+ + PO4

3- NH4MgPO4

3.3.4.

Vi vng Thiazol

Trong mi trng kim NaOH, Mg2+ to vi vng thiazol ta nh tm.

Mg2+ + vng Thiazol + NaOH ta nh tm

3.4.ION Bi3+

3.4.1.Vi NaOH

Bi3+ cho ta keo Bi(OH)3 mu trng, ta khng tan trong kim d, tan trong

acid, un nng ta sc mu vng.

Bi3+ + 3OH- Bi(OH)3

3.4.2.Phn ng thy phn

Khi pha long dung dch mui Bi

3+

to thnh ta trng ca mui bismutyl, tantrong acid long.

Bi3+ + Cl- + H2O BiOCl + 2H2O

3.4.3.

Vi Kali Iodid

Bi3+ cho ta en BiI3, ta tan trong KI thnh phc [BiI4] mu cam.

Bi3+ + 3KI BiI3 + 3K+

BiI3 + KI K[BiI4]

3.4.4.

Vi ThioureCc mui to vi thioure mt phc mu vng.

Bi3+ +2SC(NH2)2 [Bi(NH2-CS-NH2)3]3+ dung dch mu

vng.


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BI 6

CC PHNG PHP XC NH CATION NHM V

(Cu2+, Co2+, Hg2+)

Mc tiu

1. Trnh by c tn, cng thc ha hc ca thuc thnhm, thuc th nh

tnh, hin tng c trng khi cation nhm V tc dng vi cc thuc th

v vit c phng trnh ion minh ha.

2. Bit cch tch nhm V ra khi hn hp cc cation v sdng cc phn

ng c trng nhn bit cc cation nhm ny.Ni dung

1. c tnh

Cation nhm V to vi kim nhng hydroxyd khng tan trong kim d nhng

tan trong NH4OH hoc hn hp NH4OH - NH4Cl thnh cc amonicat.

Thuc thnhm: NH4OH 3M.

Cc hydroxyd KOH v NaOH vi dung dch cha cation Cu2+ cho kt ta

hydroxyd lng tnh, vi Hg2+ cho oxyd, vi Co2+ cho mui base.Cc cation nhm V c c trng bi kh nng to phc, trong dung dch

mui Hg2+khng mu; mui Cu2+, Co2+ c mu.

2.

Phn ng chung

Vi KOH, NaOH

Cation nhm V to thnh cc hydroxyd c mu khc nhau

Cu2++ 2KOH Cu(OH)2 Xanh lam+ 2K2+

Co2++ KOH + Cl-CoOHCl Lam+ K2+

Hg2++ 2KOH HgO Vng+ 2K2++H2O

Cc ta ny tan trong acid v c v trong amoniac d

Vi NH4OH


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Dung dch amoniac d phn ng vi cation nhm V to cc phc

Cu2++ 4NH4OH [Cu(NH3)4]2++ 4H2O

Co2++ 6NH4OH [Co(NH3)6]2++ 6H2O

Hg2++ 4NH4OH [Hg(NH3)4]2++ 4H2O

Cc amonicat bn tr amonicat ca Cobalt, di tc dng ca oxy trong

khng kh schuyn thnh Co3+c mu tm.

3. Phn ng nh tnh

Ion Cu2+

Vi amoni hydroxyd: Cu2+ to kt ta mu xanh l tan khi cho NH4OH

d, to phc cht mu xanh lam

Cu2++ 2NH4OHCu2(OH)22+ + 2NH4

+

Cu2(OH)22++ 8 NH4OH 2[Cu(NH3)4](OH)2+ 4H2O

Vi Kali ferrocyanid: Cu2+cho kt ta ng ferrocyanid mu thm

Cu2++ K4[Fe(CN)6]Cu2[Fe(CN)6]

Vi thuc th M.T.A (Mercuri Thiocyanat Amoni): Cu2+ phn ng vi

thuc thMTA cho ta xanh vng. Nu thm vo dung dch Cu2+mt lng

Zn2+, ta to thnh c mu tm sim.

Cu2++ Zn2++ 2[Hg(SCN)4]2-

ZnCu[Hg(SCN)4]2 tm sim

Vi Na2S2O3: Na2S2O3khi thm vo dung dch mui ng acid ha s

lm mt mu dung dch do to thnh Cu2S khng tan trong acid.

2Cu2++ 2Na2S2O3 + 2 H2O Cu2S + 2Na2S4O6

Ion Co2+

Vi NH4OH: Co2+cho mui kim CoOH+mu xanh lam, khi un nng hay

phn ng vi NaOH bin thnh Co(OH)2 mu hng, tan trong NH4OH dthnh phc mu vng nu.

Co2++ NH4OH CoOH+Co(OH)2

Co(OH)2+ NH4OH [Co(NH3)4]2++ H2O


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Vi NH4SCN: cho mu xanh m vi Co2+do to phc dphn hy trong

nc v trong acid long, tan trong dung mi hu c nh aceton.

Co2++ NH4SCN [Co(SCN)4]2+

Ion Hg2+Vi NaOH: Hg2+phn ng vi kim to ta oxyd thy ngn mu vng.

Hg2++ NaOH HgOvng

Vi NH4OH: cho kt ta trng HgNH2+tan trong NH4OH d thnh phc.

Hg2++ NH4OH HgNH2+ (Mercuri amido)

HgNH2+ + NH4OH [Hg(NH3)4]

2+

Vi Kali Iodid: Hg2+phn ng vi KI cho ta HgI2mu cam, tan khi

cho d KI to phc mu vng nht.

Hg2++ 2KI HgI2cam+ 2K+

HgI2 + 2KI K2[HgI4]

Phn ng khvi SnCl2: Hg2+phn ng vi dung dch SnCl2mi pha cho

ta trng thy ngn I, sau chuyn thnh Hg nguyn t mu xm en.

Hg2++ SnCl2Hg2 + SnCl4Hg0

Vi Na2S

2O

3: trong mi trng acid, khi un nng Na

2S

2O

3 to vi mui

thy ngn II kt ta en thy ngn II sulfur (khng tan trong acid long).

Hg2++ Na2S2O3HgS en

CU HI N TP

1.Nu tn, cng thc ha hc ca thuc thnhm V, phn ng xy ra khi cho

cation nhm V tc dng vi thuc thcha nhm?

2.Vit cng thc ha hc, hin tng c trng v phng trnh ion minh ha

ca cc phn ng nh tnh cc ion Cu2+

, Co2+

v Hg2+

?3.Phn bit Cu2+v Co2+bng thuc thno? Vit phng trnh phn ng?

4.Lm th no tch cc cation nhm V ra khi hn hp cc cation nhm I,

II, III, IV, VI v trong dung dch bt k?


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31

BI 7

CC PHNG PHP XC NH CATION NHM VI

(NH4+, K+, Na+)

Mc tiu

1. Trnh by c tnh cht c bit ca cation nhm VI, cng thc ha hc

ca thuc th cation, hin tng c trng khi cation nhm VI tc dng

vi cc thuc th v vit c cc phng ion minh ha.

2. Bit cch xc nh cc ion nhm VI thn hp cc cation nhm I, II, III,

IV, V, VI v trong hn hp ion bt k.

3.Nu c s khc nhau c bn ca cation nhm VI vi cc cation 5 nhmu khi tc dng vi natri cacbonat.

Ni dung

1. C TNH CHUNG CA CATION NHM VI

Cc ion Na+, K+l cc ion kim loi kim, ion NH4+do phn tNH3v ion H

+

to nn NH4+khng bn trong dung dch kim v nhit cao.

HNH3

4NH

OHNH4 OHNH 23

Cc hp cht hydroxyd (NaOH, KOH, NH4OH), cc mui (clorid, sulfat,

carbonat) u d tan trong nc. Do khi dng acid hoc kim lm thuc

th nhm th cc cation ca 5 nhm u u kt ta, cn cation nhm VI

khng cho ta. Cation nhm VI khng c nhm thuc th nhm. xc nh

cc cation nhm VI ngi ta tin hnh xc nh trc tip cation m khng

phn tch theo hthng.

2. PHN NG NH TNH

2.1. ION NH4+


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2.1.1. Vi NaOH: ion NH4+bNaOH phn tch thnh amoniac NH3, kh ny

bay ra c thnhn bit bng giy tm phenolphtalein, giy sc mu hng,

hoc dng giy qutm sha xanh.

NH4++ NaOHNH3 + Na++ H2ONH3 + giy tm phenolphtalein hng.

NH3 + giy qutm xanh

2.1.2. Vi thuc thNessler: trong mi trng kim NH4+cho ta mu

nu hay vng nu.

KOHHgIKNH 32 2424 7KI + 2H2O +

2.2.ION K+

2.2.1. Vi acid perclorid HClO4: K+to ra kt ta perclorat mu trng.

K+ + HClO4 KClO4 + K+

2.2.2. Vi acid tatric H2C4H4O6: Trong mi trng trung tnh hay acetic

(pH=5-7), K+cho kt ta trng.

K++ H2C4H4O6 KHC4H4O6 + H+

2.2.3. Vi thuc thacid picric:K+

cho kt ta mu vng.Phn ng nhum mu ngn la: t cc mui K+trn ngn la khng mu th

ngn la sc mu tm.

2.3.ION Na+

2.3.1. Vi thuc thKontop (km uranyl acetat): trong mi trng trung

tnh hay acid acetic, Na+cho ta vng vi Kontop.

OHCOOCHCOOCHUOZnNa 238332 9)()( OHCOOCHUOZnNa 29332 9,)()(

Tinh thvng, hnh mt nhn khi soi di knh hin vi.

2.3.2. Phn ng nhum mu ngn la: t cc mui natri trn ngn la

khng mu th ngn la sc mu vng. Phn ng rt nhy nn phi ra dy

OHg

Hg

NH2I


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bch kim tht sch trc khi tin hnh phn ng v chkt lun c ion Na+

khi ngn la mu vng tn ti vi giy trln.

CU HI N TP

1.Trnh by tnh cht chung ca cation nhm VI?2. Gai thch nguyn nhn phi xc nh cc cation nhm VI theo thtNH4

+,

K+, Na+?

3. Ktn cng thc ha hc, hin tng c trng ca cc phn ng xc nh

ion NH4+, K+, Na+v vit phng trnh ion minh ha?

4. Hy cho bit s khc nhau c bn gia catio nhm VI v cc cation 5 nhm

u khi tc dng vi thuc thnatri carbonat?

5. Lm th no xc nh cc cation nhm VI thn hp cc cation bt k?


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BI 8

CC PHNG PHP XC NH CC ANION NHM I

MC TIU

1. Trnh by c hin tng c trng ca cc anion nhm I khi tc dng

vi bari nitrat, bc nitrat v vit phng trnh ion minh ha.

2. K c tn, cng thc ha hc, hin tng ctrng ca TT xc nh cc

ion Cl-, Br-, I-, S2-, NO3- v vit phng trnh ion minh ha.

3. Thao tc ng k thut thanion nhm I vi cc TT s b, TT aion v xc

nh anion nhm I.

NI DUNG

Anion nhm I gm c: Cl-, Br-, I-,S2-.

1.

THUC TH S B

Bari nitrat: cc anion nhm I tc dng vi Ba(NO3)2khng cho kt ta v

to ra mui bari tan (BaS2, BaCl2,)Bc nitrat:

Cc ion Cl-, Br-, I-,S2- to ra cc ta mu, cc ta ny khng tan trong

HNO32N.

Cl-+ AgNO3 = NO3- + AgCl (trng)

Br- + AgNO3 = NO3- + AgBr (vng nht)

I- + AgNO3 = NO3- + AgI (vng nht)

S2-+ AgNO3 = NO3- + Ag2S (en)

2.

THUC TH XC NH ANION

Phn ng chung xc nh X-:


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Dng cht oxy ha mnh l KMnO4 trong mi trng acid sulfuric oxy

ha X-thnh halogen tdo (X2) ri nhn bit cc halogen bng thuc th c

hiu.

Phng trnh phn ng:10X-+ 2KMnO4+ 8H2SO4= 2MnSO4+ K2SO4+ 5X2+ 5SO4

2-+ 8H2O

i vi Clo (Cl2): dng thuc thl giy tm Vilier-Fayol giy chuyn thnh

mu xanh tm.

i vi Brom (Br2): dng thuc th l giy tm fluoressein, giy chuyn t

mu vng sang hng.

i vi iod (I2): dng thuc th l giy tm h tinh bt giy chuyn thnh

mu tm xanh.

Cc thuc thring ca ion Cl-, Br-, I-:

Thuc th ca Cl- l AgNO3: ion Cl- tc dng vi AgNO3 to ta trng tan

trong NH4OH.

Thuc th ca Br- l nc clor: ion Br- b nc clor oxy ha thnh brom.

Brom ha tan trong cloroform lm cho lp cloroform c mu vng nu.

Cl2+ 2Br- = 2Cl-+ Br

2

Thuc thca I-:

Thy ngn clorid: ion I- tc dng vi HgCl2 to ra kt ta , ta ny tan

trong dung dch I-d.

HgCl2+ 2I- = HgI2 + 2Cl

-

HgI2+2I- = [HgI4]

2-

Ch acetate: ion I-tc dng vi Pb(CH3COO)2to ra kt ta vng ti.

Pb2++2I- = PbI2Thuc thca ion S2-:

Ch acetate:to kt ta en.

Pb2++2S2- = PbS


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Acid v c mnh:ion S2-b cc acid v c mnh (HCl,H2SO4) phn hy to

thnh kh hydro sulfur c mi hi.

S2-+ 2H+ = H2S


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BI 9

CC PHNG PHP XC NH ANION NHM II

(AsO43-, AsO3

3-, PO43-, BO3

2-, HCO3-, CO3

2-)

MC TIU

1. Trnh by c hin tng c trng khi anion nhm II tc dng vi TT s

bv vit phng trnh ion minh ha.

2. Trnh by c phn ng chung xc nh AsO43-, AsO3

3v HCO3-, CO3

2-

v vit phng trnh ion minh ha

3. K c tn, cng thc ha hc, hin tng c trng ca TT phn bitHCO3

- v CO32-, TT ca ion PO4

3-v vit phng trnh ion minh ha

4. Thao tc ng k thut thanion nhm II vi cc TT v xc nh anion

nhm I, II.

NI DUNG

1.

THUC TH S B

Bari nitrat: cc anion nhm II tc dng vi Bari nitrat u cho ta trng, cc

ta ny tan trong HNO32N, v chng l mui ca cc acid yu nn b acidnitric phn hy.

BO2-+ Ba2+ Ba(BO2)2

AsO43-+ 3Ba2+ Ba3(AsO4)2

2AsO33-+ 3Ba2+ Ba3(AsO3)2

2PO43-+ 3Ba2+ Ba3(PO4)2

CO32-+ Ba2+ BaCO3

Ring ion HCO3- khng to c kt ta vi Ba(NO3)2 nhng b phn tch

thnh CO32-, nn cc dung dch ion HCO3

-cho ta trng vi Ba(NO3)2


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Bc nitrat:cc ion nhm II tc dng vi AgNO3u cho kt ta, cc ta ny

tan trong HNO3.

3AgNO3+ AsO33- Ag3AsO3+ 3NO3

-

(vng)

3AgNO3+ AsO43- Ag3AsO4+ 3NO3

-

(nu)

3AgNO3+ PO43- Ag3PO4 + 3NO3

-

(vng)

AgNO3+ HCO3- AgHCO3 + NO3

-

(trng)

2AgNO3+ 2CO32- Ag2CO3+ 2NO3

-

(trng)

Ta Ag2CO3lu bphn tch thnh Ag2O c mu xm.

2.

THUC THANION

2.1. Phn ng chung xc nh AsO43- v AsO3

3-:dng hydrogen mi sinh

(do Zn + H2SO42N) khAsO43-, AsO3

3- thnh kh hydroarsenid (AsH3),

kh AsH3bay ln gp giy tm AgNO3lm cho giy c mu en.Zn + H2SO4 ZnSO4+ 2H

0

3H++ AsO33-+ 6H0 AsH3 + 3H2O

3H++ AsO43-+ 8H0 AsH3 + 4H2O

Phn bit AsO33-v AsO4

3-phi da vo phn ng vi AgNO3

2.2.Phn ng ring ca ion AsO43-:ion AsO4

3-tc dng vi hn hp MgCl2

+ NH4Cl + NH4OH to ra mui kp MgNH4AsO4kt ta trng.

AsO43-+ Mg2++ NH4+ MgNH4AsO4

2.3.Thuc thchung ca HCO3-v CO3

2-:

2.3.1. Thy ngn (II) nitrat:ion HCO3-v CO3

2-tc dng vi Hg(NO3)2to

ra kt ta nu hay vng nu.


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2.3.2. Acid v c mnh hay acid acetic: ion HCO3- v CO3

2- b cc acid

mnh nh HCl, H2SO4hoc acid acetic phn hy thnh kh CO2. Kh CO2lm

c nc vi trong.

HCO3-+ H+ CO2 + H2O

CO32-+ 2H+ CO2 + H2O

CO2+ Ca(OH)2 CaCO3+ H2O

2.4.Thuc thphn bit HCO3-v CO3

2-

Dng magnesi chlorid hoc magnesi sulfat:

Ion HCO3-tc dng vi MgCl2cho ta trng

Mg2++ CO32- MgCO3

2.5.Thuc thca ion PO43-

2.5.1.Amoni molybdat:trong mi trng acid nitric, ion PO43-tc dng vi

[(NH4)2MoO4] to ra kt ta mu vng.

Ion AsO33-bHNO3oxy ha thnh AsO4

3-v tc dng vi (NH4)2MoO4tng

t nh PO43-. trnh nhm ln gia AsO3

3-vi PO43-cn xc nh AsO3

3-,

PO43-sau.

2.5.2.Hn hp MgCl2+ NH4Cl + NH4OH:ion PO43-

tc dng vi hn hpMgCl2+ NH4Cl + NH4OH to ra mui kp MgNH4PO4kt ta trng.

PO43-+ Mg2++ NH4

+ MgNH4PO4


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BI 10

CC PHNG PHP XC NH ANION NHM III

NO3-, C2O4

2-

Mui nitrat thrn khi t nng l mt cht oxy ha rt mnh v dbphn

hy. Dung dch nitrat trong nc khng c kh nng oxy ha.

1.

ION NITRAT

Phn ng vi FeSO4NO3

-l cht oxy ha mnh, khi tc dng vi FeSO4trong mi trng H2SO4,

NO3-bkh n oxyt nit, cht ny to vi FeSO4d thnh phc cht sulfat

nitrozil c mu nu xut hin ranh gii tip xc gia H2SO4 m c v

nc.

6FeSO4+ 2NO3-+ H2SO4 3Fe2(SO4)3+ 2NO + 4H2O

NO + FeSO4d [Fe(NO)]SO4

Phc khng bn, b phn hy khi b lc hay un. Tin hnh phn ng khingui.

Phn ng vi Al nguyn t

Nhm l cht khmnh, trong mi trng kim Al bkhNO3-thnh NH3.

Kh NH3bay ra lm xanh giy qu .

NO3-+ 3Al + 3 OH- NH3 + 3 AlO2

-

Diphenylamin (C6H5)2NH

Trong mi trng H2SO4m c, ion NO3-tc dng vi diphenylamin to ra

hp cht mu xanh l.

Thuc thGriess:


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Ion NO3- b hydro mi sinh(do Zn + CH3COOH) kh thnh NO2

- (hoc

HNO2) sau acid nitro(HNO2) tc dng vi TT Griess A v Griess B to ra

hp cht azoic c mu hng.

2.

ION OXALATPhn ng vi KmnO4/ H2SO4. Ion C2O4

2-trong mi trng H2SO4khMn7+

thnh Mn2+lm mt mu thuc tm v phng thch kh CO2.

5C2O42-+ 2KMnO4+ 16H

+ 10CO2+ 2Mn2++ 8H2O


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BI 11

XC NH CATION V ANION

TRONG DUNG DCH MUI V C

MC TIU HC TP

1. Trnh by c trnh t xc nh cation v anion trong DD mui v c

2. Thao tc ng kthut xc nh cation v anion trong mt DD mui v c.

NI DUNG

1. Cc th nghim s b

1.1. Xc nh c tnh ca mu

Mu phn tch c thcc dng: Rn: Ha tan vi cc dung mi thch hp ri mi phn tch.

Dung dch trong sut: phn tch trc tip

1.2. Quan st mu ca dung dch:c th gip d on mt s ion.

V d:

Xanh lam c Cu2+

Hng c Co2+

Vng c Fe3+,I-

Xanh ru c Cr3+

1.3. Ngi mi ca dung dch

Mi gim CH3COOH

Mi khai NH3

1.4. Th pH dung dch: dng giy qu th pH.

1.4.1. pH trung tnhKhng c ion dbthu phn nh Bi3+,Hg2+,...

1.4.2. pH acid

Khng c ion db phn hu mi trng acid: CO32-,...


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Khng c cc cp oxy ha- khc thphn ng vi nhau nh: MnO4-

vi I-, Fe3+vi I-,...

1.4.3. pH kim

Khng c cc ion dbta mi trng kim: Bi3+, Ca2+, Ba2+C th c cc ion lng tnh: Pb2+, Al3+, Zn2+

1.5. Cc phn ng nhn din s b

1.5.1. Cc ion to hydroxyd t tan

DD + NaOH 3M tng git. Kt ta c mu

Rst Fe3+

Trng ha mu c Mn2+

Xanh Cu2+

1.5.2. Cc ion c tnh oxy ha hay kh

1 git DD + 1git HCl + 1 git KI dd nu c thc ion c tnh oxy

ha

1 git DD + 1 git KMnO4long + 1 git HNO3 mu tm mt c

thc ion c tnh kh.

2. Trnh t xc nh cation v anion trong dung dch mui v cTrong dung dch mui tinh khit bao gicng cha mt cation v mt anion

gc acid.

V d: dung dch mui ZnSO4c cha cation Zn2+v anion SO4

2-.

Khi xc nh mui v c trong DD ngi ta tin hnh xc nh cation v

anion ri suy ra mui cn tm.

Vic xc nh cation v anion tin hnh c lp vi nhau, tuy nhin c mt s

cation gy tr ngi cho vic xc nh anion v ngc li. khc phc tr

ngi trn v trnh nhm ln cn tin hnh xc nh cation v anion theo mt

trnh tsau

2.1. Quan st dung dch gc


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NU DD gc c mu th xc nh cation c mu tng ng trc, xc nh

anion sau

Nu DD gc khng c mu th tin hnh th s b.

2.2. Thm u vi NatricarbonatNu DD gc + Na2CO3khng c ta, xc nh anion trc, xc nh cation

nhm VI ( NH4+, K+, Na+) sau.

Nu DD gc + Na2CO3c ta( trng, mu) xc nh cation 5 nhm u trc

(theo s tng qut xc nh cation, xc nh anion sau).

Ch :

Bit c anion, c thgip loi trmt scation:

C I-,Br-,Cl-khng c Ag+

C SO42- khng c Ba2+, Sr2+,Pb2+

Phn tch theo hthng da vo cc nhm thuc th

Ring mt sCation c thtm ngay tdung dch u: Zn2+, Fe3+,Bi3+,...

CU HI N TP

1. Trnh by trnh t xc nh cation v anion trong DD mui v c?2. Hy v s xc nh cation v s xc nh anion?

3. Vic nh hng tm cation v anion trong bng sau ng hay sai?

Hin tng nh hng S

DD gc + Na2CO3c ta en.

DD gc + Na2CO3 khng c

ta.

DD gc + Na2CO3c ta trng

+ cht bay hi.

Tm cation t nhm I n V trc,

tm anion sau

Tm cation trc, tm anion

sau.Tm ion Bi3+ trc, tm anion sau


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4. Hy m tli qu trnh tin hnh v vit phng trnh ion minh ha, khi

xc nh c DD gc l BaCl2?

5. Yu cu thmt l ha cht (th rn) c dn nhn Magnesi clorid tinh

khit th phi lm thno?6. Hy sdng bng kim c khng tkim tra trnh t thao tc k

thut xc nh cation v anion?


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NI QUY PHNG THC TP

LIN BMN HA PHN TCH- KIM NGHIM-C CHT

1. Mi tiu nhm thc tp gm 3 sinh vin ( nhm trng tchia 12 tiu

nhm & gi danh sch vcho Cn BPhc VGing Dy) lm chung

mt bi v chu trch nhim vbi ny trn mi phng din: trt t, kt

qu, dng c.

2. Sinh vin phi c mt ti phng th nghim trong sut bui thc tp. Sinh

vin n trqu 15 pht mt ln bkvng mt mt bui.

3. Sinh vin vng mt qu mt bui thc tp m khng c xin php vi l dochnh ng s khng c thi thc tp cui kha.

4. Nu ngh c l do chnh ng, sinh vin phi lm n xin php km giy

t xc minh l do v phi xin hc b vo bui khc vi Cn BGing

Dy.

5. u mi bui, 1 sinh vin i din nhm mnh k nhn mn dng c.

Cui bui, dng cphi c ra sch s, kim tra, k nhn trcho Cn

BPhc VGing Dy. Tiu nhm thc tp phi chu trch nhim vs

mt mt, h bdng cca tiu nhm.

6. Sinh vin phi mc o chong trng, mang bng tn khi thc tp.

7. Tuyt i cm ht thuc trong phng th nghim.

8. Khng c ci ni n o, n ung hoc lm vic ring trong khi thc

tp.

9. Khng c ngi trn bn thc tp.

10.Cui mi bui thc tp nhm trng phn cng cc tiu nhm thay nhau

vsinh phng th nghim.


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11.Trc khi vo phng thc tp, sinh vin phi c kbi l thuyt v thc

hnh ca bi thc tp.

12.Mi tiu nhm np mt bi bo co (theo mu) vo u mi bui thc tp

ca bi ktip ng 7h, 13h & 18h, sau thi im ny khng nhn & ctiu nhm phi nhn 0 im cho bi bo co .

13.im thi mi mn thc tp l 10 im.

14.Cc mn iu kin: Ha phn tch nh tnh v Ha phn tch nh lng.

Sinh vin thi thc tp 02 mn ktrn phi t im nm (5) trln mi

iu kin thi l thuyt. Ring Kim nghim thuc l mn chuyn

ngnh, im thi thc tp & l thuyt tnh c lp. Thi l thuyt gm cc

hnh thc: trc nghim MCQ, in khuyt.


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S CU TRONG PHNG TH NGHIM

Khi acid c (acid sulfuric, acid nitric,) ri ln da ph i ra ngay ch

bbng bng tia nc mnh trong vng 3 5 pht, sau dng bng tn dung

dch tannin trong ru hoc dung dch kali permanganat 3% bi nh ln vt

bng. Nu bbng bi kim c th tin hnh cu cha bc u nh trn

nhng ra bng dung dch acid acetic 2%.

Khi bacid hoc kim c bn vo mt, phi ra mt bng nhiu nc,

sau phi n ngay bnh vin.

Khi bbng bi cc vt nng (thy tinh, kim loi,) th u tin phi

bi dung dch tannin trong ru hoc dung dch KMnO43% ri bi mchng

bng. Khi bbng bng phospho cn bi chbbng bng dung dch ng

sulfat 2%.

Khi b ng c clor, brom, hydro sulfur, cacbon oxid cn a ngay

ngi bnn ra chkhng kh trong lnh.

Nu b ng c bi cc cht arsen, thy ngn cng nh cc muicyanua cn phi nhanh chng a ngi bnn n bc s.

Khi b t tay do dao hay mnh thy tinh cn lau sch mu, bi thuc

st trng (cn hay dung dch KMnO4long), sau cm mu bng dung dch

FeCl3 ri bng li.

Khi qun o ang mt trn ngi bchy mt din tch ln th tuyt i

khng c chy hoc ra chgi, phi nm xung t m ln, trng hp

chy trn din tch b th dng gi lau, dng nc hoc bt kmt phngtin no thch hp dp tt chchy, tuyt i khng c dng bnh cha

chy (thng l cha CO2) phun vo ngi ang bchy qun o, m phi

dng nc di hay trm kn bng chn.


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CCH S DNG DNG C, THUC TH

V MT S THAO TC C BN

1. DNG C

1.1. ng nghim

Ra v trng

v bha cht, trng bng nc my.

Cbng chi ui chn, ra bng nc my, trng li bng nc ct.

unDng kp ghay kp kim loi, cm phn cn di.

Thtch dung dch khng c qu ng nghim.

un mt thong ca lp dung dch trn ngn la, va un va lc, lun lun

phi hng ng nghim vpha khng c ngi.

un xong, trnh t ng nghim ang nng vo ni m t.

1.2. Pipet

Trc khi dng phi ra sch bng nc my, trng li bng nc ct.Mi pipet chdng mt loi thuc th.

Dng khn hay gi sch thm git thuc th d ng u pipet, khng c

vy xung nn gch.

1.3. n cn

Khng c nghing n t, phi dng giy mi, giy cn chy khng

c vt vo st rc.

Dng chp nha tt ngn la, khng c thi.

Nu cn cn m n t khng chy, phi ly tim n ra vt ht nc ri lp

li v t.

1.4. Ni cch thy


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Mc nc bn ngoi lun bng hay cao hn mc nc trong ng nghim

Nn nh shay lm du ring trnh nhm ln.

1.5. My ly tm

Dung dch cha trong ng nghim khng c qua t thtch.Lun phi c 2 ng t i xng nhau trn my v cha nhng lng dung

dch tng ng.

y np trc khi my chy, chmnp khi my ngng hn.

Phi nh du ng nghim trnh nhm ln.

2. THUC TH

Thng sp xp thnh 2 loi:

2.1. Thuc thtrong hp g

Gm cc loi thng thng nh acid, base long, mt smui.

2.2. Thuc thtrn k

cc acid v base m c, thuc th c hiu, thuc thnhm.

c ktn, cng thc ha hc, nng trc khi dng.

i vi cc acid, base m c (NH4OH, HNO3, HCl,...) phi y np sau khi

ly.

Dng pipet ring cho mi loi thuc th.

3. MT S THAO TC C BN

3.1. Cch dng giy chththpH

C 2 loi: quxanh v qu xanh. Cho 1 mu nh, di khong

0.5 cm, t ln chsch kh. Dng a khuy nhng vo dung dch cn xc

nh pH, chm mt git dung dch ln giy, quan st s i mu.

3.2. Lm phn ng kt taLy khong 1 ml (20 git) dung dch cn thnghim cho vo ng nghim ri:

Thm tng git thuc th,va thm va lc (nu l ta tinh th)

Thm ttcho ht lng thuc thch nh ri lc (nu l ta v nh hnh).


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Mun ta hon ton th sau khi cho thuc th ta phi lc k, ly tm ri

thm mt git thuc ththeo thnh ng nghim vo lp nc trong pha trn.

Nu cn c ta l thuc th cha , phi thm tip vi git thuc th, ly tm

v thli n khi khng cn ta na.

3.3. Tch ring ta v dung dch

Sau khi ly tm, lc qua giy lc hoc cn thn gn dung dch bn trn qua ng

nghim khc, trnh lm xao ng dung dch v nu khng smt ta.

3.4. Ra v ha tan ta

Cho mt t nc ct (khong 1ml), vo ng nghim, lc mnh, nu cn th ly

tm ri b nc ra hay nhp vo dung dch tch ta. Lp li nh th 2 n

3 ln.

Sau khi ra sch, ta c ho tan hon ton bng cch thm tng git

dung mi thch hp (nc, acid, base ...). Lc u sau mi ln thm. un nh

hay un si tu theo yu cu ca tng cht cho n khi ta tan hon ton.

Trnh cho d nhiu acid hay base v scn trcc phn ng sau.

3.5. Quan st mu dung dch hay ta

Cc phn ng to phc thng cho ra nhng phc mu tan hay khng tan, khi

thc hin phi ch n pH ca dung dch.

Quan st mu: nhn trn nn trng.

Quan st skhng mu hay dung dch c t ta: nhn trn nn en.


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53

BI 1

XC NH CC CATIONNHM I (Ag+, Pb2+, Hg22+)

1.

DNG C - HA CHT THUC TH

Dng c

n cn

a thy tinh

ng nghim cc loi

ng nghim ly tm

My ly tm

Ha cht, thuc th

1. K2CrO40,5 M

2. KI 0,5M

3. HCl 6M

4.NH4OH

5.NaOH 6M

6. H2SO43M

7. HNO3

8. Dy ng

9. HNO33M

2.

THC HNH

2.1. Tm Ag+

2.1.1. Vi HClAg+ + Cl-AgCltan / NH4OH m c [Ag(NH3)2]Cl

Ly 5 git Ag+ + 1 git HCl 6M trng vn. Ly tm ly ta, thm

NH4OH m c tha tan (do to thnh [Ag(NH3)2]+). Acid ha li

bng HNO3m c trli.

2.1.2. Vi KI

Ag+ + I- AgI (ta ng vng)

Ly 5 git Ag+ + 2 git I-ta ngvng.

2.2.

Tm Pb2+

2.2.1. Vi HCl


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Pb2+ + Cl- PbCl2 (trng hnh kim, tan / nc nng)

Ly 5 git Pb2++ 1git HCl 6Mtrng. Ly tm ly ta, thm 20 git

nc ct un nng tan.

2.2.2. Vi KI

Pb2++ I- PbI2(ta vng tan/ nc nng)

Ly 5 git Pb2++ 1 git I- ta vng. Ly tm ly ta. Thm 10 git

nc ct. un nng tan. Lm lnh t ngt ta hnh vy mu vng

ng nh.

2.2.3. Vi K2CrO4

Pb2+

+ CrO4PbCrO4vng, tan trong NaOH 6MLy 5 git Pb2++ 1 git K2CrO4vng. Thm NaOH 6M tha

tan.

2.2.4. Vi H2SO4

Pb2++ SO42-PbSO4trng

Ly 5 git Pb2++ 1 git H2SO4trng.

2.3. Tm Hg22+

2.3.1. Vi HCl

Hg22++ Cl- Hg2Cl2trng vn (Calomel)

Hg22+ Hg0+ HgNH2Cl en xm

Ly 10 git Hg22++ 1 git HCl 6M trng. Ly tm ly ta, thm

vi git NH4OH m c en xm.

Hg2Cl2+ 2NH4OH HgNH2Cl + Hg0 + NH4Cl + 2H2O

2.3.2. Vi dy ngHg2

2++ Cu0Cu2++ Hg0en

Nhng dy ng vo dung dch Hg22+dy Cu b en. H nng dy

ng li sng (Hg thng hoa).

NH4OH


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3.

S PHN TCH MT VI CATION NHM I

AgCl, PbCl2 , Hg2Cl2 II...VI

PbI2vng

Pb2+Cl- AgCl, Hg2Cl

2

PbCrO4 vng Hg ,HgNH2Cl [Ag(NH3)2]+

AgCl

(Ag+)

HNO3H+

trng

en xm

(Hg22+

)

Dung dch u

+ HNO33M H+

+ HCl 6M n ta hon ton. Ly tm

Ra ta (1ml ED + 2 HCl 6M)10 git ED. un nng. Ly tm

Chia 2 NH4OH . Lc klytm

1 git KI 1git K2CrO4

Ta Dch

(Pb2+

)


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Bi 2

XC NH CATION NHM II(Ba2+, Ca2+)

1.

PHN NG NH TNH CA ION Ba2+

1.1. Vi tc nhn c SO42-: H2SO4, (NH4)2SO4,..

Ba2+ + SO42-trng

Ly 5 git Ba2++ 2 git H2SO4 3M ta trng

1.2. Phn ng Voller

Ly 5 git Ba2+, thm 1 git thuc thKMnO4, thm 5 git H2SO4 3M,

c kt ta, ly tm, sau thm H2O2 t t tng git n khi dung dch mtmu hng tm cn kt ta c mu hng.

1.3. Vi (NH4)2CO3

Ba2++CO32-BaCO3tan trong CH3COOH 6M, axit v c

Ly 5 git Ba2++ 1git CO32-trng. Thm CH3COOH 6M tha

tan.

1.4. K2CrO4

Ba2+ + CrO42-BaCrO4vng, khng tan trong CH3COOH

6M, thm CH3COOH 6M tha vn khng tan

1.5. (NH4)2C2O4

Ba2++C2O42-Ba2C2O4trng

Ly 5 git Ba2++ 2git C2O42-trng.

2.

PHN NG NH TNH CA ION Ca2+

2.1. Vi H2SO4

Ca2++ SO42-CaSO4(chta khi [Ca

2+] kh c hay c cn 960)

Ly 10 git Ca2++ 2 git SO42-+ 5 git C2H5OH 96

0trng


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2.2. Vi NH4)2CO3:thc hin tng t nh Ba2+

2.3. Vi (NH4)2C2O4

Ca2++C2O42-CaC2O4trng, khng tan trong CH3COOH

Ly 5 git Ca2++ 2 git (NH4)2C2O4+ 1git NH4OH . un nh

trng

3. S PHN TCH CATION NHM II

Dung dch uDung dch u

NH4OH OH-

Na2CO3bo ho n ta hon tonun nng. Ly tm. Bdd.Ra ta.Ho ta li bng CH3COOH 6M.

+ (H2O +H2SO43M + cn 900 ).

+ Na2CO3bo ho, dun si kgnB nc. Lm 3 ln

Ra ta 2 ln, bng ncCH3COOH 6M (ha tan)K2CrO4cho d n ta hon ton.

III ... VI

( Ba2+)

(vng)

NaOH 3Mlc k

(NH4)2SO450% ng lngCT 15 pht. Ly tm

NH4OH trung tnh1 git NH4OH10 git (NH4)2C2O4BM (15). Ly tm

PbO22-

BaSO4, CaSO4,(PbSO4)

BaCO3, CaCO3,(PbCO3)

Trng

dd Ca2+,CrO42-PbCrO4,BaCrO4

CaC2O4

dd Ca2+

dd Ca2+BaCrO4

+ H2SO43M n ta hon tonun nng, ngui, thm 1/2 thtch cn 90o+ H2SO43M n ta hon tonun nng, ngui, thm 1/2 thtch cn 90o


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Bi 3

XC NH CATION NHM III (Al3+, Zn2+)

1.

PHN NG NH TNH CA ION Al3+

1.1. Vi NH4OH, NaOH

Al3++ 3OH-Al(OH)3bng trng + OH- AlO2

-+ 2H2O

AlO2-+NH4

+ + 2H2O Al(OH)3 + NH4OH

Ly 5 git Al3+ + 1 git NaOH 3M bng trng xut hin. Thm

NaOH 3M tha, ta tan, tip tc thm bt NH4Cl, un nng, ta xut hin tr

li.Ch : mun thy ta ca Al(OH)3 ta phi thm NaOH t t theo thnh

ng nghim, v ta ny tan rt nhanh trong mi trng NaOH.

1.2. Vi thuc th aluminon

Al3++ Aluminon Ta bng , khng bphn hy

bi NH4OH v (NH4)2CO3

Ly 5 git Al3++ 5 git Aluminon + 10 git m acetat. un nng thm

NH4OH 2N ti khi c mi NH3ri cho 2 3 git (NH4)2CO3bng

Ion cn tr: Fe3+, Cr3+, Ca2+, Cu2+, Bi3+,...

2. PHN NG NH TNH CA ION Zn2+

2.1.Vi NH4OH

Zn2++ 2OH-Zn(OH)2 [Zn(NH3)4]2++ H2O

Ly 5 git Zn2++3 git NH4OH 3M trng. Thm NH4OH d

tan.

2.2. Vi NaOH

Zn2++ 2OH-Zn(OH)2 ZnO22-(Zincat) + 2H2O

t0

CH3COO-/CH3COOH

+ NH4OH d

NaOH


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Ly 5 git Zn2++ 2 git NaOH 3M Zn(OH)2trng. Thm NaOH

6M d tan.

2.3.Vi thuc th M.T.A:(NH4)2[Hg(SCN)4] (Mercuri Thiocyanat Amoni)

Zn2++ Cu2++2[Hg(SCN)4]2- ZnCu[Hg(SCN)4]2

Ly 10 git Zn2++ 1 git Cu2++ 2 git M.T.A tm sim

Ch :mi trng trung tnh, lng Cu2+phi t , nu tha Cu2+, kt ta

s tm en.

III. PHN TCH CATION NHM III

Dung dch c cc cation III,IV,V

Ta nhm IV,V AlO2 ,ZnO22-

Al(OH)3 [Zn(NH3)4]2+

Al3+

bng

(Al3+

)

Zn2+PbCrO4vng(Cr3)

tm xim

(Zn2+

)

CH3COOH 6MH+

Pb(CH3COOH)2

* Cu2+

* MTA

NaOH 3M d + vi git H2O2un k n ht bt.

un siNH4Cl bo ha 5gitun kvi git

NH4OH . Ly tm

Ho tan bng HNO33M

Aluminonm acetatun nh


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BI 4

CC PHNG PHP XC NH CATION NHM IV

Fe3+, Mn2+, Mg2+ & Bi3+

THUC THNHM: NaOH 3M,& H2O2

1.

PHN NG NH TNH

1.1.

ION Fe3+

1.1.1. Vi NH4OH

Fe3++ 3OH Fe(OH)3 nu .

Ly 5 git Fe3+ + 1 git NH4OH nu .

1.1.2.

Vi Kaliferrocyanid K4[Fe(CN)6]

4Fe3++ 3[Fe(CN)6]4- Fe4[Fe(CN)6]3 xanh ph.

Ly 5 git Fe3++ 1 git K4[Fe(CN)6] xanh ph.

1.1.3.

Vi thuc thKSCNFe3++ 3SCN- Fe(SCN)3 mu.

Ly 5 git Fe3++ 1 git KSCN dung dch mu.

1.2. ION Mn2+

1.1.1.

Vi NaOH

Mn2+ phn ng vi NaOH cho ta trng Mn(OH)2. lu ngoi khng kh

hoc khi c shin din ca H2O2schuyn thnh mu nu MnO2.

Mn2++ NaOH + H2O2 MnO210 git Mn2++ 3 git NaOH v thm 5 git H2O2 ta nu,...

1.1.2.

Phn ng oxy ha


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Vi tc nhn oxy ha mnh nh PbO2/HNO3, Mn2+boxy ha thnh Mn7+c

mu tm.

Ly 10 git Mn2++ mt t bt PbO2+ 5 git HNO3 un nng

dung dch c mu tm.Ch : trong dung dch tm Mn2+phi khng c c cc ion mang tnh kh

nh Cl-, Br-, I-. Nu c phi loi trc bng AgNO3.

1.3. ION Mg2+

1.1.1.

Vi NaOH, NH4OH

Mg2++ 2OH- Mg(OH)2 ta trng.

1.1.2.

Vi Na2HPO4/NH4Cl- NH4OH

NH4OH/ NH4Cl

Mg2++ Na2HPO4 ta trng hnh sao hay hnh l

tan trong acid. (Nu khng c NH4OH NH4Cl ta dng v nh hnh).

Ly 10 git Mg2++ 2 git NH4Cl + NH4OH OH- + 3 git Na2PO4

ta trng.

1.1.3.

Vi thuc thvng Thiazol

Mg2++ vng Thiazol + NaOH ta nh tm.

Ly 10 git Mg2++ 1 git vng Thiazol + NaOH 6M OH-, lc

nh. Quan st ta trn thnh ng nghim c mu nh tm.

1.4.

ION Bi3+

1.1.1.

Phn ng thy gii: (pH trung tnh hay hi acid)

Bi3++ Cl-+ H2O + 2H++ BiOCl trng tan trong acid mnh.

Ly 5ml nc ct + 1 git NH4Cl + 1 git Bi3+ trng

1.1.2. Phn ng Stanit kim (SnCl2/NaOH)

2Bi3++ 3SnO22-+ 6OH- 2Bi + 3SnO3

2- + 3H2O

Ly 3 git SnCl2+ 10 git NaOH 3M. Lm lnh + 1 git Bi3+ en.

1.1.3.

Vi Thioure


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Bi3++ 2SC(NH2)2 + 3A- [Bi(NH2-CS-NH2)3]

3+ +3A-

Ly 5 git Bi(NO3)3 + mt t bt Thioure dung dch vng.

II. PHN TCH CATION

Nhm IV, V Nhm III

HNO3Nhm IV, V

Nhm VHydroxyt nhm IV

Na2CO3thong cNH4OH d

NH4Cl bo ha

Dung dch u III, IV, V

TmMn2+ Ta en Bi3+ muFe3+

PbO2HNO3un nng

SnCl2NaOH KSCN

Fe3+, Mn2+, Bi3+ nh tm Mn2+

NaOHThiazol

Fe(OH)3, MnO2, Bi(OH)3 Mn2+


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BI 5

CC PHNG PHP XC NH CATION NHM V

I. CC PHN NG NH TNH

1.Tm Cu2+

1.1. NH4OH

Cu2+ + NH4OH long Cu(OH)2 NH4OH d

[Cu(NH3)4]2+

Ly 5 git Cu2++ 2 git NH4OH 3M ta xanh Thm NH4OH va

d dd xanh da tri.

1.2. M.T.A (Mercuri Thiocyanat Amoni)Cu2++ Zn2++ ( NH4)2[Hg(SCN)4]2 CuZn[Hg(SCN)4]2tm sim

Ly 1 git Cu2++ 5 git Zn2++ 2git MTA tm sim.

1.3. Na2S2O3

2Cu2++3S2O32-+ H+ Cu2S + S4O6

2-+H2O

Ly 5 git Cu2++ 3 git Na2 S2O3+HCl 3M un nng en

2. Tm Hg2+

2.1. Vi NH4OH

HgCl2 NH2HgCl trng NH4OH d

[Hg(NH3)4]2+

Ly 5 git HgCl2+ 3 git NH4OH 3M trng. Thm NH4OH d

tan

2.2. SnCl2

SnCl2 + 2 HgCl2SnCl4 + Hg2Cl2trng Hg0

enLy 5 git SnCl2 + 5 git HgCl2en xm

2.3. KI

Hg2++ 2I-HgI2cam + 2I- [HgI4]

2-khng mu

un

NH4OH


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Ly 10 git Hg2++ 1 git KI theo thnh ng nghim . Thm KI d

tan.

Cc cation nhm V trc tiptdung dch u:c thtm trc tip tdung

dch u: Cu2+, Hg2+.

Tm Cu2+: 1 git DD + 5 git km + M.T.Atm sim.

Hg2+ : dng thuc thSnCl2 en xm, hoc dng TT KI to kt

ta cam thm d KI ta tan y l phn ng phn bit vi Hg22+

.


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65

BI 6

XC NH CATION NHM VI (NH4+, K+, Na+)

KHNG C THUC THNHM

1. PHN NG NH TNH

1.1. ION NH4+

1.1.1.Vi NaOH

NH4+ + OH- NH3 + H2O

Ly 5 git NH4++ NaOH 6M OH-. un nh, bt u ng nghim bng

giy qu thm t bng kh NH3 lm giy qu chuyn sang mu xanh.1.1.2.Thuc thvi Nesstler ( hn hp HgCl2+ KI)

KOHHgIKNH 32 2424 7KI + 2H2O +

Ly 5 git NH4++ 3 git Nesstler + 2 git NaOH 6M nu .

Ch : xc nh NH4+ta thbng chai phn ng v chai phn ng u

dng tnh th mi nh danh chnh xc ion NH4+.

1.2. ION K+

1.2.1.Vi HClO4

K++ HClO4 KClO4 trng

Ly 10 git K++ 5 git HClO4 . Lm lnh trng

1.2.2.Phn ng vi thuc thGarola Na3[Co(NO2)6].

Thuc thGarola gm Garola A: Co(NO3)2, Garola B: NaNO2

2K+ + Na3[Co(NO2)6] K2H+[Co(NO2)6] vng ngh

Ly 10 git K++ 5 git Garola A Co(NO3)2+ mt t NaNO2+ 5 git

CH3COOH lc vng ngh.

mi trng OH-hay H+mnh thuc thbph hy. NH4+cho dung dch

mu vng.

OHg

HgNH

2I


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1.3. ION Na+

1.3.1. Vi thuc thKontop ( km uranyl acetat)

OHCOOCHCOOCHUOZnNa 238332 9)()( OHCOOCHUOZnNa 29332 9,)()(

Tinh th vng, hnh mt nhn.

10 git Na++ CH3COOH 6M H++ 10 git thuc th Kontop. un si lm

lnh di vi nc, yn 10 pht, thnh thong dng a thy tinh cvo

thnh ng nghim.

iu kin: mi thng trung tnh hay hi acid (acid acetic), mi trng aicd

mnh ta tan.

Cc ion NH4+, K+, Ca2+, Sr2+, Ba2+, Al3+, gy trngi.

2. PHN TCH CATION

Cc cation nhm VI tm trc tip tdung dch u.


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S PHN TCH TNG QUT 6 NHM CATION THEO

PHNG PHP ACID BASE

Ly Tm

Ly Tm

Ly Tm

Dung dch phn tch cation

Nhm I: (ta clorid)AgCl, Hg2Cl2, PbCl2

Nc ly tm +H2SO42N

Nhm IV: (dung dchphn tch): NH4

+, Na+, K+

Nhm II: (ta sulfat)BaSO4, CaSO4, (SrSO4)

Nc ly tm+ NaOH 2N d

(+ H2O2)

Nhm III: (nc ly tm cha oxoanion)AlO2

+, ZnO22-, (SnO3

2-, CrO42-)

Kt ta(oxyd, hydroxyd nhm(IV + V)

+ HNO3(+ H2O2)

Nhm IV: (ta hydroxyd)Fe(OH)2, Fe(0H)3,

Bi(OH)3, MnO2, Mg(OH)2

Nhm V:(nc ly tm cha phc amino)Cu(NH3)4

2+Hg(NH3)42+,

(Ni(NH3)42+, Co(NH3)6

+,Cd(NH3)42+

Nc ly tm+ Na2CO3ti thong c

+ NH4OH c(+H2O2)

Ta HsbO3(hoc Sb2O5.H2O)Ha tan bng HCL cXc nh Sb:

- Phn ng thy phn- Thu c thCaille-Viel

+ HCL 6NL tm

Sb3+,5+c thxp nhm IV do to tahydroxyd/acid, khng to phc amoniacat/hoc xp ring


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BI 7

XC NH ANION NHM I: Cl-, Br-, I-, S2-, NO3-

THUC THNHM: AgNO3/HNO3

1.

PHN NG NH TNH HALOGENID

1.1. ION Cl-

1.1.1.Vi AgNO3

Ag+ + Cl- AgCl trng vn, tan trong NH4OH, (NH4)2CO3

[Ag(NH3)2]+

Thc hin:5 git Cl-+ 1 git AgNO3 trng. Thm (NH4)2CO3d,

ta tan.

1.1.2. Phn ng oxy ha thnh Cl2

10Cl-+ 2MnO4-+ 16H+ 5 Cl2+ Mn

2++ 8H2O

Kh Cl2bay ln lm xanh giy tm Orto Toludin.

Thc hin:10 git Cl-+ 4 git H2SO4 + 2 git MnO4-. Bt u ng nghim

bng giy tm Orto Toludin, quan st mu xanh tm.

1.2. ION Br-

1.2.1. Vi AgNO3

Ag++ Br- AgBr vng nht

Thc hin:5 git Br-+ 1 git AgNO3 vng nht. Ly tm ly ta. Thm

NH4OH tha ta tan.1.2.2.Phn ng oxy ha thnh Cl2

2 Br-+ Cl2 2Cl-+ Br2(nu) + Cl2 2BrCl vng nht.

t0


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Thc hin:5 git Br-+10 git CHCl3+ nc Cl2bo ha tng git lc u

nu. Thm nc Cl2d vng nht.

1.3. ION I-

1.3.1. Vi AgNO3

I-+ Ag+ AgI vng kem, khng tan trong NH4OH, (NH4)2CO3.

Thc hin:10 git I-+ 1 git AgNO3 vng kem. Chia ta lm 2 ng

nghim. ng (1) thm NH4OH. ng (2) thm (NH4)2CO3lc u.

1.3.2.Phn ng vi nc Cl2

2I-+ Cl2 2Cl-+ I2tm/CHCl3+ Cl2 2ICl khng mu.

Thc hin: 10 git I-+ 10 git CHCl3+ nc Cl2 tng git lp

CHCl3mu tm (sau khi lc u) thm Cl2d mt mu.

2. ION S2-

Pb2++2S2-=PbS

(kt ta en)

Thc hin:5 git dung dch S2-, thm 5 git Pb(NO3)2, c ta en.

III.TM ANION NHM I

2.1.Tm I-

v Br-

Thc hin:10 git dung dch u + 10 git CHCl3+ nc Cl2tng git. Lc

mnh, quan st lp CHCl3

Mu tm, nh thm nc clo mt mu: c I-

Mu vng m + nc clo vng lt: c Br-

Tm vng: c I-v Br-

2.2.Tm Cl-

Nu khng c I-v Br-: lm nh nh tnhTrng hp c I-v Br-: ly 10 git dung dch u + 1 git HNO3+ AgNO3

n ta hon ton. Ly tm ly ta.Thm (NH4)2CO3, un nng. Ly tm ly

dung dch, thm 1 git HNO3nu dung dch c trli c Cl-.


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BI 8

XC NH ANION NHM II

SO42-, BO2-, PO4

3-, CO32-, HCO3

-

THUC THNHM: BaCl2

1.PHN NG NH TNH

1.1. ION SO42-

1.1.1. Phn ng vi BaCl2

Cho ta trng BaSO4. Ta khng tan trong acid v c.

SO42-

+ Ba2+

BaSO4 trngTin hnh:10 git SO4

2-+ 2-3 git BaCl2 ta trng. Thm vi git HNO3

ta khng tan.

1.1.2. Vi Pb(CH3COO)2

Phn ng gia Pb2+vi SO42-cho ta PbSO4khng tan trong HNO3, tan trong

kim.

Tin hnh:10 git SO42-+ 2-3 git Pb(CH3COO)2 ta trng. Thm

vi git HNO3 ta khng tan.

1.2. ION BO2-

1.2.1. Tc dng ca BaCl2

Dung dch borat c tc dng vi BaCl2cho ta trng Ba(BO2)2. ta tan trong

CH3COOH.

BO2-+ BaCl2 Ba(BO2)2

Tin hnh:10 git BO2-+ 3-4 git Ba2+ ta trng. Thm CH3COOH

ta tan.

1.2.2. Vi cn etylic

BO2-phn ng vi C2H5OH cho ete borat etyl (C2H5O)3BO3. Cht ny chy

cho ngn la mu xanh lc.


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BO3-+ 3C2H5OH (C2H5O)3BO3

Tin hnh: ly 20 git dung dch H3BO3, c n cn kh. ngui, thm

1ml H2SO4. Lm ngui, thm 20 git C2H5OH un si, t ming ng nghim

ngn la mu xanh l.

1.3. ION PO43-

Cc mui phosphat tn ti: PO43-, HPO4

2-, H2PO4-.

1.3.1. Phn ng vi BaCl2

HPO42-phn ng vi BaCl2to thnh ta BaHPO4. Ta ny tan trong HCl v

CH3COOH.

HPO42-+ Ba2+ BaHPO4

Tin hnh: 10 git HPO42-+ 3-4 git Ba2+ ta trng

1.3.2.Vi hn hp Mg2+(Mg2+, NH4Cl v NH4OH)

HPO42-cho ta kt tinh trng MgNH4PO4. Ta khng tan trong NH4OH.

HPO42-+ Mg2++ NH4OH + NH4Cl MgNH4PO4

Tin hnh:10 git Mg2+ + 5 git NH4Cl + 5 git HPO42-+ 5 git NH4OH

ta trng.

1.3.3.Vi amoni molypdat (NH4)2MoO4Ion phosphat tc dng vi amoni molypdat trong HNO3 cho ta mu vng

amoniphosphomolypdat.

H3PO4+ 12(NH4)2MoO4+ 21HNO3 (NH4)3PO4.12MoO3.2H2O

Tin hnh:10 git PO43-, un cn bt + 3 git HNO3+ 3 git NH4NO3+ 6

git phosphomolydat, un nh xut hin ta mu vng

1.4. ION HCO3-

1.4.1.Vi acid mnh v c mnh hay acid aceticHCO3

-+ H+ CO2+ H2O

(lm c nc vi trong)


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Tin hnh:nh5 git dung dch ion HCO3-, thm CH3COOH tng git, quan

st ng, thy c kh bay ra.

1.4.2.Vi Hg2+

Hg2++ HCO3- Hg(HCO3)2

(ta nu hoc vng nu)

Tin hnh: nh5 git dung dch ion HCO3-, thm 5 git Hg(NO3)2, c ta

nu hoc vng nu.

1.5. ION CO32-

1.5.1.Vi acid mnh v c mnh hay acid acetic

CO32-+ H+ CO2+ H2O

(lm c nc vi trong)

Tin hnh:nh5 git dung dch ion HCO3-, thm CH3COOH tng git, quan

st ng, thy c kh bay ra.

1.5.2.Vi Hg2+

Hg2++ CO32- Hg(CO3)2

(ta nu hoc vng nu)

Tin hnh: nh5 git dung dch ion HCO3-

, thm 5 git Hg(NO3)2, c ta nu hoc vng nu.

1.5.3. Vi Mg2+

Mg2++ CO32- MgCO3(ta trng)

Tin hnh:nh5 git dung dch ion CO32-,thm 5 git MgCl2,c ta trng.

2. TM ANION NHM II

2.1.Tm SO42-

Tin hnh:10 git dung dch u + 2 git HCl 6M ly tm bta nu

c. Ly dch ly tm + 2 git BaCl2 ta trng c SO42-

2.2. Tm BO2-,PO4

3-:lm nh nh tnh.

2.3. Tm HCO3-v CO3

2-:lm nh nh tnh


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S XC NH ANION NHM I V II

NO3-

Cl-

I-, Br-

Khng kt ta

Dd gc + Ba(NO3)2 Dd gc + AgNO3kt t

a tr

ng

kt ta vng

kt ta en

S2-

kt ta trng

+ HNO32N

tan

Dd gc + AgNO3kt ta nu

kt ta vngAsO43-

AsO33-, PO4

3-

kt ta trng

DD gc + CH3COOHKh

DD gc + Hg(NO3)2 kt ta nu

DD gc+

MgCl2

kt ta trng

Khng kt ta

CO32-

HCO3-


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BI 9

XC NH ANION NHM III (NO3-, C2O4

2-)

1.PHN NG NH TNH

ION NO3-

Phn ng vi FeSO4

Fe(II) kh nitrat n nit oxyd, cht ny to vi mui st d hp phc

[Fe(NO)]SO4lm dung dch nhum mu nu.

NO3-+ Fe2++ H+ NO + Fe3++ 2H2O

NO + FeSO4d [Fe(NO)]SO4Tin hnh: ly 2 ng nghim

ng (1): FeSO4khong ht bp + 10 git H2SO4. ngui.

ng (2): 10 git NO3-+ 5 git H2SO4. Lm lnh.

t tng (2) vo ng (1) theo thnh ng nghim, ni tip gip gia hai

lp cht lng xut hin mt vnh nu.

Phn ng khnitrat bng Al kim loi

Trong mi trng kim Al kim loi khNO3-n amoniac.

2Al3++ NaOH 2NaAlO2+ 2H+

Hydrogen mi sinh khNO3-thnh amoniac

2NO3-+ 18H+ 2NH3+ 6H2O


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Tin hnh: 10 git NO3-+ 5 git NaOH + mt t bt nhm. y ming ng

nghim bng ming giy qu . Kh bay ln lm giy qu c mu xanh.Ch

tm Al3+bng phn ng ny vi iu kin trong dung dch khng c ion NH4+

ION OXALATVi KMnO4/H2SO4

Ion C2O42-lm mt mu ca thuc tm.

5C2O42-+ 2KmnO4+ 16H

+ 10CO2 + 2Mn2++ 8H2O

Tin hnh: 10 git C2O42- + 4 git H2SO4 + tng git KmnO4, un nng

mt mu tm.


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BI 10

PHN TCH HN HP CATION V ANION

TRONG DUNG DCH

1.

Dng cha cht thuc th

C y bdng c, ha cht v thuc thca tt ccc bi phn tch

cation v anion trc .

2.

Thc hnh

Khi nhn c dd hn hp cation v anion cn nh tnh, phi thc hin ln

lt cc bc phn tch sau:

Dng gic quan nhn xt mu sc, mi. a ra d on ban u vcc ionc mt.

Thc hin cc php th s bv:

pH ca dung dch.

Mu ngn la.

T d on tip vcc ion c thc mt.

Thmt sphn ng, c bit l phn ng ca cc thuc th nhm i vi

cation v anion.

Theo , tip tc d on cc ion c thc trong dung dch phn tch.

Tin hnh phn tch h thng hoc na h thng theo cc s thc hnh

phn tch cation v anion.

Sau khi c kt lun vcc cation v anion va tm c tphn tch hthng,

cn i chiu kt lun y vi cc kt qu th s b ban u xem c g mu

thun. Nu cn nghi ngth phi tin hnh phn tch li.

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Noi Dung Giao Trinh Hptdinh Tinh Duoc Trung 2012