4th and 5th Form Qualitative Analysis

8/12/2019 4th and 5th Form Qualitative Analysis

1/5

Qualitative Analysis Page 1of 5

Tests involving the reagent aqueous NaOH solution ONLY

TABLE 1. COLOURED SOLUTIONS

Ion First addition of reagent Reagent in excess Coents

Pale geen !"e#$%

Dity geen &&t

"e#$!a'% $ #O()!a'%

"e!O(%#!s%

No fut*e +*ange, *o-eve at t*e

to& of t*e i/tue it ay tun

0o-n on staning

This is due to oxidation of iron(II)

hydroxide to iron(III) hydroxide

Basi+ *yo/ie -*i+* eans it

oes not ea+t -it* e/+ess NaO(

solution

2ello- !"e3$% Rusty 0o-n &&t

"e3$!a'% $ 3O()!a'%

"e!O(%3!s%

No fut*e +*ange Basi+ *yo/ie -*i+* eans it


solution

Blue !Cu#$% Pale 0lue &&t

Cu#$!a'% $ #O()!a'%

Cu!O(%#!s%

No fut*e +*ange Basi+ *yo/ie -*i+* eans it


solution

Big*t geen

!C3$%

Blue o 0lue geen &&t

C3$!a'% $ 3O()!a'%

C!O(%3!s%

P&t issolves foing a 0ig*t

geen solution

C!O(%3 !s% $ 3O()!a'%

4C!O(%563)!a'%

These ions are not on

the C!"C s#lla$us

and thus can $e

ignored $# %thand 5thfor students

Pin7!Co#$% Blue &&t -*i+* tuns &in7 onstaning

Co#$!a'% $ #O()!a'%

Co!O(%#!s%

No fut*e +*ange

Pale &in7 0utusually

+olouless

!8n#$%

9*ite o +ea &&t

8n#$!a'% $#O()!a'%

8n!O(%#!s%

No fut*e +*ange, *o-eve &&tay tun 0o-n on staning

This is due to oxidation of Mn(II)

hydroxide to Mn(III)oxide

TABLE #. COLOURLESS SOLUTIONS

Ion First addition of reagent Reagent in excess Coents

Ca#$ No &&t No &&t

N(:$

No &&tOn warming, a colourless pungent

gas is evolved which turns red

litmus to blue

N!"(a#) "O

$(a#)N%(g) "

&O(l)

No &&t Aonia gas is t*e ONL2al7aline gas you -ill eet at

t*is level;

8g#$ 9*ite &&t

8g#$!a'% $ #O()!a'%

8g!O(%#!s%

No fut*e +*ange

Ba#$ Little o no &&t No fut*e +*ange Baiu *yo/ie is vey

solu0le *en+e no &&t

Al3$ 9*ite &&t

Al3$!a'% $ 3O()!a'%Al!O(%3!s%

Dissolves to fo a +olouless

solutionAl!O(%3 !s% $ 3O(

)!a'%

4Al!O(%563)!a'%

All t*ee *yo/ies of in+ate,

aluinate an &lu0ate

es&e+tively.


2/5


3/5

Qualitative Analysis Page )of 5

T(,L" 5- Tests .ith various reagents other than sodiu h#droxide and aqueous aonia

Test O$servation Inference Coents

Silve nitate solution in

t*e &esen+e of ilute

(Cl o (NO3

T*en follo-e 0y

a'ueous aonia

9*ite &&t eans

&&t issolves to give a

+olouless solution

Cea &&t&&t &atially issolves

2ello- &&t

&&t eains

Cl)&esent

Ag$!a'% $ Cl)!a'%AgCl !s%

AgCl !s% $#N(3!a'%4Ag!N(3%#6$

B)&esent

Ag$!a'% $ B)!a'%AgB !s%

I)&esent

Ag$!a'% $ I)!a'%AgI !s%

ilver chloride ppt

turns from white togrey

in sunlight as the silver

ions are reduced to

silver which gives the

ppt a grey or evenpurple colour

Baiu +*loie o

0aiu nitate solution

T*en follo-e 0y ilute(Cl o (NO3

9*ite &&t

&&t issolves to give a+olouless solution

&&t eains

SO3#)o SO:

#)&esent

SO3#)&esent

SO3#)

!a'%$ #($

!a'% SO#!g%$ (#O !l%

SO:#)&esent

Ba#$!a'%$ SO:#)

!a'%BaSO:%s%

Dilute niti+ o

*yo+*loi+ a+i ust

0e &esent to &event

t*e &e+i&itation of+a0onates.

Aition of (Cl o any

sou+e of +*loie ions

sometimes an additional

test may be to warm themixture if a ppt is

formed and then allow

to cool

9*ite &&t

&&t issolves fully -*en

i/tue is -ae ane+ystallises to fo

neele s*a&e +ystals

-*en +ool

P0#$

P0#$!a'% $ #Cl)!a'%P0Cl#!s%

lea!II% +*loie is

oe solu0le in *ot

-ate t*an +ol -ate.

T*eefoe one -oulsee a total eu+tion in

t*e aount of &&t

&esent -*en i/tue is

-ae. As it +ools,+ystalli>ation o++us

an t*e tue s*a&e of

t*e +ystals ae seen.

N, lead/II0 $roide

gives a siilar

o$servation $ut it is

onl# artiall# solu$le

in hot .ater .hile

lead/II0 chloride is

coletel# solu$le in

hot .ater

Aition of a'ueous&otassiu ioie

solution o aition of

P0#$ions

sometimes an additional

test may be to warm the

mixture if a ppt is

formed and then allow

to cool

Big*t yello- &&t

Re)0o-n solution -*i+*

ay *ave 0la+7 &ati+les.

P0#$

P0#$!a'% $ #I)!a'%P0I#!s%

Potassiu ioie is a eu+ing agent

an if a +olou +*ange is seen, t*en a

eo/ ea+tion *as o++ue an t*e

sa&le *as o/ii>ing &o&eties.

lea!II% ioie is oesolu0le in *ot -ate

t*an +ol -ate. A

&atial eu+tion in t*e

aount of &&t &esent

-*en i/tue is

-ae -oul 0e seen.

As it +ools,

+ystalli>ation o++usan t*e tue s*a&e of

t*e +ystals ae seen.

Often t*e +ystals


4/5

Qualitative Analysis Page %of 5

e/*i0it a ?glittey@

effe+t.Con+. sul&*ui+ a+i to a

soli *alie e.g. soiu+*loie, soiu 0oie,

soiu ioie

igouous effeves+en+e

-*ite i/tueColouless, &ungent gas

Tuns 0lue litus e


oangee i/tue

0o-n, &ungent gasTuns 0lue litus e t*en

-*ite


ee& &u&le0la+7 i/tue

&u&le, &ungent gas

Tuns 0lue litus e t*en

-*ite

Cl)&esent

as is a+ii+as is *yogen +*loie

is&la+eent of *yogen +*loie 0y

sul&*ui+ a+i

NaCl $ (#SO:(Cl $ Na(SO:

B)&esent

Boie ions ae stong eu+ing agents

an a eo/ ea+tion o++us an 0oine

is &ou+egas is a+ii+ an it also 0lea+*es -*i+*

i&lies t*e *alogen is 0eing &ou+e

(#SO:$ #($$ #B)B#$ SO#$

#(#O

I)&esent

Ioie ions ae stong eu+ing agents

an a eo/ ea+tion o++us an ioine is&ou+e

gas is a+ii+ an it also 0lea+*es -*i+*

i&lies t*e *alogen is 0eing &ou+e

(#SO:$ ($$ I):I#$ (#S $ :(#O

Con+entate

sul&*ui+

a+i is a

&o-efulo/ii>ing

agent

Aition of a+iifie

&otassiu anganate

solution

De+olouisation i.e. fo

&u&le to +olouless

Sin+e a+iifie &otassiu anganate is

an o/ii>ing agent, t*e sa&le teste

ust *ave eu+ing &o&eties

Aition of a+iifie

&otassiu i+*oate

solution

oes fo oange to geen Sin+e a+iifie &otassiu i+*oate is

an o/ii>ing agent, t*e sa&le teste

ust *ave eu+ing &o&eties

Aition of ilute a+i to a

soli sa&le eit*e ilute

(Cl o (NO3

Effeves+en+e

Soli issolves

No effeves+en+e

Soli issolves

as &ou+e

sa&le ust 0e eit*e a +a0onate o a

sul&*ite

Sa&le ust 0e eit*e an o/ie o

*yo/ie

Aition of Devaas

alloy to sa&le in &esen+e

of NaO( solution an-a

Effeves+en+e

Colouless, &ungent gas

evolve tuns e litus 0lue

as is 0asi+

as is aonia

NO3)ion &esent

3NO3)$ Al $ FO(G$ 1(#O H 3N(3

$ 4Al!O(%:6G

Aition of +on+ (#SO:

-it* +o&&e tunings

&esent an -a

Effeves+en+e

Blue)geen solution

Bo-n, &ungent gas evolve

Tuns 0lue litus e

as is a+ii+

NO#gas &ou+e !0o-n gas%

NO3)ion &esent

3Cu!s% $ (NO3!a'% )) 3Cu!NO3%#!a'% $#NO!g% $ :(#O!l%

T*e +on+ sul&*ui+ a+i

ea+ts -it* t*e nitate

ion to fo niti+ a+i.

T*e niti+ a+i t*en

ea+ts -it* t*e +o&&etuning to fo nitogen

ono/ie -*i+* is

o/ii>e to nitogen

io/ieAition of fes*ly

&e&ae ion!II% sul&*ate

solution o +ystals ant*en a +on+ (#SO:

slo-ly

Bo-n ing is foe NO3)&esent

NO3)$ 3"e#$$ :($H 3"e3$$ NO $ #(#O4"e!(#O%56

#$$ NO H 4"e!(#O%F!NO%6#$

!0o-n ing%

T*e 0o-n ing is not

al-ays easily seen, it is

a +onfiation test t*at

t*e nitate ion is &esent


5/5

Documents

4th and 5th Form Qualitative Analysis