PUC-II Chemistry 2006

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.

10x1=10

1. Out of carbon and zinc which is a stronger reducing agent ?

2. Why is Fe 3 + ion more stable than Fe 2 + ion ?

3. If the rate of the reaction is independent of concentration of the reactant,

    what is the order of the reaction ?

4. Which noble gas is not adsorbed by charcoal ?

5. What is hydronium ion ?

6. What is the only factor on which the colligative property value depends ?

7. Between potassium nitrate and aluminium nitrate which one is required in

    minimum concentration to coagulate arsenious sulphide sol ?

8. Which is the organic product obtained when methyl magnesium iodide

    reacts with formaldehyde followed by acid hydrolysis ?

9. Name the least stable cycloalkane.

10. How many amino acid units are present in insulin ?

PART – B

Note:   i) Answer any ten questions.

ii) Each question carries two marks.

10 X 2 = 20

11. Justify that concentrated sulphuric acid is a good dehydrating agent with

      example.

12. Calculate the bond order in oxygen molecule.

13. The time for half-life of a first order reaction is found to be 30 mins. What

      is the rate constant of the reaction ?

14. Define Faraday’s first law of electrolysis.

15. What is a spontaneous reaction ? Explain with an example.

16. What is Tyndall effect ? Explain.

17. Calculate the number of particles present in the unit cell of BCC.

18. Distinguish between inductive effect and electromeric effect.

19. Explain the effect of the following substituents on the acidity of phenol :

i) — CH 3 group

ii) — NO 2 group.

20. How is ethanamine prepared from ethane nitrile ?

21. What are reducing and non-reducing sugars ? Give one example each.

22. What are biological messengers ? Give an example.

PART – C

2x5=10

I. Answer any two of the following :

23.       a) How are noble gases separated by Dewar’s charcoal adsorption

method?                                                                                              3

b) With the help of the Ellingham’s diagram, explain why silver

oxide can be thermodynamically decomposed at relatively lower

temperature.                                                                                       2

24.       a) Give the postulates of Werner’s theory of coordination

compounds.                                                                                        3

b) Copper (I) compounds are white and diamagnetic whereas

Copper (II) compounds are coloured and paramagnetic. Give

reason.                                                                                                2

25.       a) Describe the manufacture of sodium hydroxide using

Nelson’s cell.                                                                                       4

b) Write the IUPAC name of [CO (NH3)4 Cl 2 Cl2]C1.

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

26.       a) Discuss the molecular orbital structure of benzene.                     3

b) Explain geometrical isomerism with an example.                          2

           

27.       a) What is S N 1 mechanism ? Explain it using hydrolysis t-butyl

bromide.                                                                                              3

b) Give any two uses of aniline.                                                         2

28.       a) Write the Howarth’s ring structure for â-D ( – ) fructopyranose. 2

b) Define the term ‘iodine value of an oil’. Mention its significance.  2

c) What is isoelectric point of amino acids ?                                      1

29.       a) Write the equations for the following reactions :                            4

i) Mixture of calcium formate and calcium benzoate is dry

distilled

ii) Acetaldehyde is treated with hydroxyl amine

iii) Acetone is treated with hydrogen cyanide

iv) Phenol is heated with a mixture of conc. nitric acid and

conc. sulphuric acid.

b) How do you convert Methane to Ethane ? 1

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

30.       a) How are the molecular orbitals formed by the linear combination

of atomic orbitals ?                                                                             3

b) Distinguish between ideal and non-ideal solutions.                        2

31.       a) Calculate the mass of potassium acetate that should be

dissolved in 500 cm 3 of 0·02 M acetic acid solution to prepare

a buffer solution of pH 4·6.

Given K a = 1·8 X 10^-5.                                                                       3

b) Define the following terms :                                                             2

i) Protective colloid

ii) Gold number.

32.       a) Discuss the application of the principles of solubility product

with respect to the analysis of II and IV group basic radicals.            3

b) The standard free energy change ( Δ G° ) for a reaction is

– 115 kJ at 27°C. Calculate the equilibrium constant ( K p ).             2

33.       a) Derive an expression for the velocity constant of a first order

reaction.                                                                                              4

b) Acetic acid very weakly dissociates in presence of hydrochloric

acid. Give reason.                                                                               1

34.       a) With diagram, explain the construction and working of standard

hydrogen electrode. Give two limitations. 4

b) Define radius ratio in ionic crystals. 1

PART – D

IV. Answer any one of the following :                                                                         1X10=10

35.       a) Explain the chemical reactions that occur during the extraction

of iron from haematite by smelting in a blast furnace.                                   3

b) What is angle strain ? Calculate the angle strain in cyclobutane.              3

c) What is a pseudounimolecular reaction ? Give an example.                     2

d) Calculate the e.m.f. of the cell prepared by combining

Zn | 1 M ZnSO 4 and Cu | 1 M CuSO 4 at 298 K.

Given E 0

Zn = – 0·76 V and E 0

Cu = + 0·34 V . 2

36.       a) On the basis of Valence bond theory, explain hybridisation,

geometrical shape and magnetic property in Cuprammonium

sulphate.                                                                                                          3

b)         i) Explain Perkin’s reaction with an example.                                    2

ii) How is acetic acid prepared from ethanol ?                                   1

c) Calculate the osmotic pressure of 10% solution of glucose

at 27°C. Given R = 8·314 JK – 1 mol – 1 .                                                       2

d) Give any two demerits of Arrhenius theory of ionisation.                          2

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

37.       a) Explain the preparation of m-dinitrobenzene from nitrobenzene.              3

b) Describe Acrolein test.                                                                               2

38.       Describe an experiment to show the effect of temperature on the rate

of the reaction between potassium persulphate and potassium

iodide.                                                                                                              5

39.       Describe the experiment to determine the mass of Mohr’s salt

crystals in one dm 3 solution by using standard potassium

dichromate solution. Give the equation for the reaction involved.                 5