04.Sr_Chem.pdf

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Board of Intermediate EducationSenior Inter - Chemistry

Model Paper (English Version)Time : 3 Hours Max. Marks: 60

SECTION - A

Note: 1) Very Short Answer type questions.

2) Answer ALL questions. 10 × 2 = 20

1. What are lipids? Give one example.

2. What is peptide linkage? Give an example.

3. How Paracetamol is prepared? Give equation.

4. What are antibiotics? Give an example.

5. State first law of thermodynamics. Give mathematical formulation of this law.

6. What is "Gibbs energy"?

7. Mention the names of monomers used in the preparation of

a) Bakelite b) Nylon c) Terylene d) Neoprene.

8. What is Williamson's synthesis? Give equation.

9. What is Cannizzaro reaction? Give equation.

10. How many moles of AgCl are produced on addition of AgNO3 solution to 1 M

CoCl3. 5 NH3 solution. How many moles of ions are formed by complete

ionization of 1 mole of CoCl3. 5 NH3?

SECTION - B

Note: 1) Short Answer type questions.

2) Answer any SIX questions. 6 × 4 = 24

11. Define Molality (m). What is the molality of 15% W___W

solution of H2SO4.

12. Derive Bragg's equation.

13. Give Nernst equation for metal ion electrode and non metal electrode. Calculate

the electrode potential of the following single electrode.

Ag+ (0.01 M) /Ag; (E° = 0.799 V)

14. Define the terms order and molecularity of a reaction.

15. What is emulsion? How are emulsions classified? Give examples.




16. Explain froth flotation process.

17. Explain how Super Phosphate of Lime is manufactured?

18. a) Write the formulae of the following compounds.

i) Tetra Ammine Copper (II) Sulphate

ii) Tri Chloro triammino Cobalt (III)

b) Write the IUPAC names of the following compounds.

i) K3[Fe(CN)6] ii) [Pt(NH3)6](SO4)2

SECTION - C

Note: 1) Long Answer type questions.

2) Answer any TWO of the following. 2 × 8 = 16

19. a) How is bleaching powder manufactured industrially?

b) Give the reactions of Ozone with the following.

i) Ag2O ii) KI iii) PbS iv) BaO2

20. a) Explain four factors that influence the rate of reaction.

b) Explain the Lewis acid-base theory with suitable examples.

21. a) Explain the preparation of Ethyl alcohol from molasses.

b) How Ethyl alcohol reacts with

i) CH3MgI ii) CH3COOH

iii) Na metal iv) H2SO4, 140°C




ANSWERSSECTION - A

1. What are lipids? Give one example.

A: Naturally occurring water insoluble oily compounds related to fatty acids, esters

of fatty acids. e.g.: Fats, Waxes.

2. What is peptide linkage? Give an example?

A: Amide linkages present between amino acids is called peptide linkage.

e.g.: Alanyl glycyl alanine.

3. How paracetamol is prepared? Give equation.

A: Para amino phenol on acetylation gives paracetamol.

4. What are antibiotics? Give an example.

A: The chemical substance produced by microorganism that destroy or inhibit the

growth of disease causing micro organism is called antibiotic.

e.g.: PENICILLIN

5. State first law of thermodynamics. Give mathematical formulation of thislaw.

A: Energy can neither be created nor destroyed but energy in a process may be

converted from one form to another form.

Q = W + ∆E

6. What is Gibbs energy?

A: The difference between enthalpy (H) of a system and the product of absolute

temperature (T) of system and entropy (S) is called Gibbs energy.

∆G = ∆H − T∆S

7. Mention the names of monomers used in the preparation of

a) Bakelite b) Nylon c) Terylene d) Neoprene

A: a) Bakelite : Phenol & HCHO

b) Nylon : Adipic acid & Hexa methylene diamine

c) Terylene : Terepthalic acid & ethylene glycol



OH

NH2 CH3COOH

(CH3CO)2O→

OH

NHCOCH3




d) Neoprene : 2 - chloro 1, 3 - butadiene

8. What is Williamson's Synthesis? Give equation.

A: C2H5Cl on reaction with Sodium ethoxide to form diethyl ether.

C2H5O Na + Cl C2H5 → C2H5 O C2H5 + NaCl

9. What is Cannizaro reaction? Give equation.

A: Aldehydes having no α - hydrogens reacts with strong alkali to undergo

disproportionation reaction.

10. How many moles of AgCl are produced on addition of AgNO3 solution to1 M CoCl3. 5 NH3 solution. How many moles of ions are formed bycomplete ionization of 1 mole of CoCl3. 5 NH3?

A: 2 Moles of AgNO3 are formed on addition of AgNO3 to the complex. 1 Mole

CoCl3. 5 NH3 on complete ionization gives 3 moles of ions.

SECTION - B11. Define molality (m) ? What is the molality of 15% W___

Wsolution of H2SO4?

A: Number of moles solute present in one litre solvent is called molality.

Wt. of Solute × 1000m =

gram molar Wt. of Solute × Wt. of Solvent

15 × 1000= = 1.8

98 × 85

12. Derive Bragg's equation.

A: A crystal has many planes.

Atoms or ions are arranged in

systematic geometry in these

planes. Atoms or ions are

arranged in these planes in

order. When X - rays incident

on these planes, they undergo

diffraction. When the waves

H Hconc.NaOH

C = O + C = O → H − C− OH + H − C − OK

H H H

H O

1st plane

2nd plane

3rd plane

First ray

Second ray

X - ray diffraction at the atoms in a crystal plane


are diffracted from these atoms or ions, they may have constructive or destructive

interference. From the figure, it is very clear that 1st and 2nd ray are travelling the

same distance up to A and D. Where as 2nd X - ray travels an extra distance

DB + BC (Path difference) than that of 1st X - ray. If the two waves are to be

present in the same phase, the path difference must be equal to the wave length λ

or an integral multiple of wave length.

DB DBIn ADB triangle, sin θ = =

AB d

∴ DB = d sin θ

BC BCIn ABC triangle, sin θ = =

AB d

∴ BC = d sin θ

∴ nλ = DB + BC = 2d sin θ

∴ nλ = 2d sin θ is known as Bragg's equation.

13. Give Nernst equation for metal ion electrode and non metal electrode.Calculate the electrode potential of the following single electrode.

Ag+ (0.01 M)/ Ag; (E° = 0.799 V)

0.0591A: For metal ion electrode E = E° + log Cn

0.0591For non metal ion electrode E = E° − log C

n

E° = 0.799 V, C = 0.01 M, n = 1

0.0591... E = E° + log C

n

0.0591= 0.799 + log [10−2]

1

= 0.799 − (2 × 0.0591)

= 0.680 V.

14. Define the terms order and molecularity.

A: Order: The sum or the powers of the Concentration terms in the rate equation

of the reaction is called order. Order is determined experimentally. This can

have values including zero, negative, positive, fractional values.

Molecularity: Number of atoms or ions or molecules participating in rate

determining step. This is known theoretically from the reaction mechanism.




This can have values 1 or 2 or 3.

15. What is emulsion? How are emulsion classified? Give examples.

A: Emulsion is a colloidal system in which both the dispersion medium and

dispersed phase are liquids.

Oil in water type emulsion: The emulsion in which oil is dispersed phase

and water is dispersion medium.

e.g.: Milk, Vanishing Cream.

Water in oil type emulsion: The emulsion in which water is dispersed phase

and oil is dispersion medium.

e.g.: Cold cream, Cod liver oil.

16. Explain froth flotation process.

A: Powdered Sulphide ore is taken in a tank. Water, pine oil frothing agent like

sodium ethyl xanthate are added to this ore. Contents are agitated by bubbling air.

The froth is formed and carries the ore particles with it. The gangue particles set-

tle down at the bottom of the tank. The froth is stabilised by adding collectors.

They prevent the ore particles from wetting with water. Sulphide ore particles float

on water with froth. Copper pyrites, iron pyrites are concentrated by this method.

17. Explain how super phosphate of lime is manufactured?

A: Super phosphate of lime is a mixture of Calcium dihydrogen phosphate and

gypsum. It is manufactured by treating finely powdered phosphate rock or bone

ash with Chamber's acid (70% H2SO4).

Ca3(PO4)2 + 2 H2SO4 + 4 H2O → Ca(H2PO4)2 + 2 (CaSO4. 2 H2O).



1. Mixer

2. Stirrer

3. Chamber acid

4. Valves

5. Brick work Dens

6. Waste gases

MANUFACTURE OF SUPERPHOSPHATE OF LIME


In this process finely, powdered phosphate rock and calculated quantity of

Chamber's acid are taken into cast iron mixer. It is stirred with stirrer. The charge

is dumped alternatively into one of the Dens D1 or D2 with the help of the valves

V1 and V2. The reaction mixture is allowed in Dens for 24 to 36 hours. CaCO3,

CaF2 impurities are removed as CO2 & HF. Temperature of this mixture is raised

to 373 K. Final product is called super phosphate. To avoid waste hard mass

gypsum, it is converted into triple phosphate, which is completely soluble in

water and taken easily by the plants.

Ca3(PO4)2 + 4 H3PO4 → 3 Ca (H2PO4)2

18. a) Write the formulae of the following compounds.

i) Tetra ammine copper (II) sulphate

ii) Tri chloro triammine cobalt (III).

b) Write the IUPAC names of the following compounds

i) K3[Fe(CN)6] ii) [Pt (NH3)6] (SO4)2

A: a) i) [Cu(NH3)4]SO4 ii) [Co(NH3)3 Cl3]

b) i) Potassium Hexa Cyano Ferrate (III)

ii) Hexa amine platinum (IV) sulphate

SECTION - C

19. a) How is bleaching powder manufacturedindustrially.

b) Give the reactions of ozone with the follow-ing

i) Ag2O ii) KI iii) PbS iv) BaO2

A: a) Bleaching powder is prepared by Bachman's

plant. It consists cast iron tower. A number of

horizontal shelves fitted with rotating rakes are

present in it. Dry slaked lime is dropped through

the hopper present at the top. Cl2, hot air are sent

through inlets present at the bottom. According to

principle of counter currents, Ca(OH)2, Cl2 move

in opposite directions to form bleaching powder.

it is collected in the receiver.



Bachmann's plant preparationof CaOCl2

1. Hot air inlet 2. Cl2 inlet3. Hopper 4. Outlet gases5. Horizontal shelves6. Rotating rakes 7. Receiver8. Bleaching powder


b) i) O3 reacts with Ag2O to give Ag

Ag2O + O3 → 2 Ag + 2 O2

ii) O3 oxidises moist KI to I2

2 KI + H2O + O3 → 2 KOH + I2 + O2

iii) O3 oxidises PbS to PbSO4

PbS + 4 O3 → PbSO4 + 4 O2

iv) O3 reduces BaO2 to BaO

BaO2 + O3 → BaO + 2 O2

20. a) Explain the 4 factors that influence the rate of reaction.

b) Explain Lewis acid - base theory with suitable examples.

A: a) The chemical nature of the reactant: A reaction taking place between ionic

compounds is faster than the reaction taking place between covalent

compounds. The reaction between Ag+ & Cl_

is faster than the reaction.

N2 (g) + 3 H2 (g) 2 NH3 (g).

Because covalent compounds involve breaking of existing bonds and making of

new bonds take time.

Concentration of reactants: The rate of the reaction increases with the

concentration of reactants. If the concentration increases, number of molecules,

collisions among them increases to increase the rate.

dc− = K. Cn

dt

Effect of temperature: The rate of a reaction increases with increase in the

temperature of the reaction. For every rise of 10°C, specific rate gets doubled.

Kt + 10°C ≈ 2

KtoCEffect of Catalyst: Reactions in presence of a positive catalyst, the path of the

reaction changes in which activation energy is low and rate of the reaction is

more.

MnO2e.g.: 2 KClO3 → 2 KCl + 3 O2

b) Lewis Acid: Any substance that accepts electron pair to form a coordinate

covalent bond. e.g.: BCl3, BF3.




Types of Lewis acids:

★ All cations: e.g.: Co+3, Fe+3

★ Elements with electron sextet: O, S

★ Molecules with multiple bonds: CO2, SO2

★ Molecules with available d-orbitals: SF4, SiF4

★ Molecules with incomplete octet: AlCl3, BCl3Lewis base: Any substance that donates electron pair to form a coordinate

covalent bond. e.g.: H2O, NH3.

Types of Lewis bases:

★ All anions: F−, Cl−

★ Molecules with lone pairs: R O. .. . H, N

. .H3.

★ Molecules with multiple bonds: C2H2, C2H4.

21. a) Explain the preparation of Ethyl alcohol from molasses.

b) How ethyl alcohol reacts with

i) CH3MgI ii) CH3COOH

iii) Na metal iv) H2SO4, 140°C

A: Ethyl alcohol is prepared from the waste liquid molasses, left after the

crystallisation of sugar from sugarcane juice. Molasses contain 30-40%

sucrose. It is diluted with water to contain 10% sucrose. H2SO4 is added to

maintain pH = 4. Ammonium sulpahate & Ammonium phosphate are added

as food for Yeast. It is allowed for fermentation for 1-3 days at 30°C.

Reactions taking place during fermentation are

InvertaseC12H22O11 + H2O → C6H12O6 + C6H12O6

Glucose Fructose

Zymase C6H12O6 → 2 C2H5OH + 2 CO2

Glucose or Fructose (wash)

Wash on fractional distillation followed by distillation with CaO gives 100%

ethyl alcohol.

i) It forms alkane on reaction with grignard's reagent.

C2H5O H + CH3 MgI → CH4 + Mg(OC2H5)I

ii) It forms ester on reaction with CH3COOH.




H3O+CH3CO OH + H OC2H5 → CH3COOC2H5 + H2O

iii) It forms sodium ethoxide on reaction with Na

C2H5O H + Na → 2 C2H5ONa + H2

C2H5O H + Na

iv) It reacts with Conc. H2 SO4 at 140°C to form diethyl ether.

Conc.H2SO4C2H5 OH + H OC2H5 → C2H5OC2H5 + H2O.

140°C



(Prepared by A.N.S. Sankar Rao)

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04.Sr_Chem.pdf