Karnataka 2nd PUC CHEMISTRY (March, 2009) Question Paper

Code No. 34

March, 2009
CHEMISTRY

Time : 3 Hours 15 Minutes ] [ Max. Marks : 90

Instructions : i) The question paper has four Parts.
ii) Parts A, B, C and D are common to all the candidates.
iii) Part A carries 10 marks. Each question carries one mark.
Part B carries 20 marks. Each question carries two marks.
Part C carries 40 marks. Each question carries five marks.
In Part D — D 1 carries 10 marks and D 2 carries 10 marks. Each question of D 2 carries five marks.
iv) Write balanced chemical equations and draw diagrams
wherever necessary.

PART – A
Note : i) Answer all the 10 questions.
ii) Questions have to be answered in one word or in one
sentence each. Each question carries one mark. 10 × 1 = 10

1. What is the role of limestone in the extraction of iron from haematite ?
2. Hydrogen sulphide gas cannot be dried using conc. H 2 SO 4 . Give reason.
3. Which one among Cu + 1 and Cu 2 + salts is coloured ?
4. What is the limiting value of degree of dissociation of an electrolyte at infinite dilution ?
5. Sea-water freezes below 273 K. Why ?Code No. 34 10
6. Define electrophoresis.
7. The coordination number of a crystal is 6. What is the geometry of the crystal ?
8. Name the gas liberated when bromoethane is heated with alcoholic potash.
9. Phenol does not react with sodium bicarbonate. Why ?
10. Name the protein present in hair.

PART – B
Note : i) Answer any ten questions.
ii) Each question carries two marks. 10 × 2 = 20

11. Draw Ellingham diagram for the formation of oxides of aluminium and magnesium. Which one of these metals acts as better reducing agent
above 1500°C ?
12. How does potassium dichromate solution react with potassium
hydroxide ?
13. Calculate the EAN value of the central metal ion in tetramine copper (II) sulphate.
14. Sketch the shapes of bonding and antibonding molecular orbitals formed
when two S orbitals undergo LCAO.
15. A first order reaction is 50% completed in 80 min. Calculate the rate constant of the reaction.
16. Mention any two characteristics of an ideal solution.
17. pH value of a sample of mango juice is 4·54. Calculate the [ H + ].
18. Identify A, B, C and D in the following equation :
CH 3 – CH 2 – Cl A → CH 3 – CH 2 – OH B→ CH 3 – COOH
NaOH → C NaOH + CaO heat → D .
19. What is Wurtz-Fittig reaction ? Write the general equation.
20. Write the equations for the following reactions :
i) Dry distillation of calcium acetate
ii) Reaction of phosphorous pentachloride with acetic acid.
21. Write the Haworth structure of α – D – maltose.
22. What happens when tristearin is heated with potassium hydroxide
solution ? Give the equation.

PART – C

I. Answer any two of the following questions : 2 × 5 = 10

23. a) Describe the manufacture of ammonia by Haber's process. 3
b) Sketch the shapes of nickel tetracarbonyl. Which type of
hybridisation is involved in the formation of this compound ? 2
24. a) How is a mixture of noble gases separated by Dewar's charcoal
method ? 3
b) Write the electronic configuration of lithium molecule. Comment
on its magnetic property with reason. 2Code No. 34 12
25. a) State any three postulates of Werner's theory of co-ordination
compounds. 3
b) On the basis of electron gas theory, explain bright lustre of
metals. 2

II. Answer any three of the following questions : 3 × 5 = 15

26. a) What is mesomeric effect ? What type of mesomeric effect is
shown by – CHO group in benzaldehyde ? 2
b) Explain the mechanism of nitration of benzene. 3
27. a) How is phenol isolated from coal tar ? 3
b) What is a dipeptide ? How many peptide linkages are present in
a tetrapeptide ? 2
28. a) What is optical activity ? Which one of the following compounds
shows optical isomerism ? 2
Br — C — Br
H
CH3
Br — C — COOH
OH
CH3
b) How is ethyl bromide converted into ethyl isocyanide ? Write the
equation. 2
c) Give a chemical reaction to show that a molecule of glucose
contains a carbonyl group. 113 Code No. 34
29. a) Calculate angle strain in cyclobutane. 2
b) Explain carbylamine reaction for a primary amine. Write general
equation. 2
c) One mole of a given amine consumes two moles of methyl iodide
for exhaustive methylation. What type of amine is this ? 1

III. Answer any three of the following questions : 3 × 5 = 15

30. a) Derive an expression for rate constant of a first order reaction.
4 b) State Schultz-Hardy rule. 1
31. a) Explain buffer action in acidic buffer containing mixture of
acetic acid and sodium acetate. 3
b) When the same amount of electricity passed through solutions
of copper sulphate and hydrochloric acid, 64 mg of copper is
deposited on the cathode in the first case. Calculate the volume
of hydrogen obtained in the second case at S.T.P.
( Equivalent weight of Cu = 32 ).
32. a) Mention two limitations of standard hydrogen electrode. 2
b) Write Nernst equation for single electrode potential. Explain any
two terms in the equation. 2
c) Mention the dispersed phase and dispersion medium in a gel.
1Code No. 34 14
33. a) Define entropy. What happens to entropy when a liquid
vaporises ? 2
b) What is Brownian movement ? How is it caused ? 2
c) Define unit cell. 1
34. a) Calculate the change in free energy for the cell
Mg | Mg
2 +
( 1 m )
 Ag
+
( 1 m )
| Ag
if E o Ag = 0·8 V and E o Mg = – 2·37 V. 2
b) State any three postulates of Arrhenius theory of electrolytic
dissociation. 3

PART – D

D 1

IV. Answer any one of the following : 1 × 10 = 10

35. a) Describe Parke's process for the desilverisation of Argentiferrous lead. 3
b) Why are transition elements and their compounds good
catalysts ? Explain. 2
c) For a reaction, the graph of rate of the reaction against molar
concentration of the reactant is a straight line parallel to the
concentration axis. What is the order of this reaction ? Give an
example for such a reaction. 215 Code No. 34
d) The value of standard free energy of formation of ammonia at
298 K is – 16·6 kJ mol– 1 . Calculate the equilibrium constant
K p for the reaction. 2
e) What is iodine value ? 1
36. a) Give the mechanism of Cannizzaro's reaction. 3
b) A current of dry air was passed through a solution containing
5·4 g of an aromatic compound in 61·2 g of diethyl ether and
then through the solvent. The loss in mass of solution bulb was
0·708 g and that in the solvent bulb was 0·035 g. Calculate the
molecular weight of the aromatic compound.
( Given molecular weight of diethyl ether = 74 ) 2
c) When NH 4 Cl and NH 4 OH are added to a solution containing
Al3 + and Zn 2 + ions, only Al ( OH ) ,3 precipitates. Give reason. 2
d) i) Write the IUPAC name of
CH 3 — CH — CH 2 — COOH
Cl ii) Out of CH 3 — CH — CH 2 — COOH
Cl and CH 3 — CH 2 — CH — COOH Cl
which one has higher pKa value ? 2
e) How many Lattice points are present in a unit cell of CsCl ? 1Code No. 34 16
D 2

V. Answer any two of the following : 2 × 5 = 10

37. a) How is m-nitrobenzene prepared in the laboratory from
nitrobenzene ? Write the equation. 3
b) Mention a general test for
i) Protein
ii) Carbohydrate. 2
38. Describe an experiment to show that acid hydrolysis of methyl
acetate follows first order kinetics. 5
39. For the estimation of potassium permanganate ( KMnO 4 ) using
standard ferrous ammonium sulphate —
i) Write the chemical equation for the reaction involved.
ii) Give the equivalent weight of potassium permanganate.
iii) Name the indicator used.
iv) What is the colour change at the end point ?
v) Write the equation for calculating mass / dm 3 of potassium
permanganate in a given solution from its normality. 5

Karnataka 2nd PUC CHEMISTRY (March, 2009) Question Paper

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