COUNCIL OF HIGHER SECONDARY EDUCATION, MANIPUR

SAMPLE QUESTION, 1999

CHEMISTRY

( THEORY )

Full Mark - 70

Pass Mark - 21

Time : 3  hours

Special Instructions :

(i) There are 36 questions in all.

(ii) All questions are compulsory.

(iii) Questions of numbers 1 to 12 are of very short answer type of 1 mark each.

(iv) Questions of numbers 13 to 17 are of objective type. Each question carries 1 mark and out of the four choices given, only one is correct. Rewrite the question number and the correct answer in the answer script.

(V) Questions of numbers 18 to 27 are of short answer type of 2 marks each. each.

(vi) Questions of numbers 28 to 33 are of short answer type of 3 marks each.

(vii) Questions of numbers 34 to 36 are of long answer type of 5 marks

(viii) Marks are indicated at the right side margin of each question.

(ix) Use of long table is allowed.

 
1.  State Hess's law of constant heat of summation.  1
2.

 Of the two moving particles A and B the momentum of B is double that of A. Which of them describes the shorterwave length?

1
3.

At 250 C the equivalent conductance of a 1.011 M acetic acid is 1.433 sm2mol-1. If the  equivalent conductance at infinite dilution be  387. 9 sm2 mol-1. Calculate its degree of ionization.

1
4. What is the energy of activation of a reaction? 1
5. The rate of a reaction was found to be equal to the rate constant at any concentration of the reactant. What is the order of the reaction ?  1
6.  Write the structural formula of 2-methyl phenyl acetic acid. 1
7.  Give an example of a double salt. 1
8.  Why is catalyst, in general, used  in the form of finely divided powder ?  1
9. Write the repeat limit of PVC.  1
10. What is glycoside linkage ? 1
11.  What are pheromones ? 1
12.  Why is malathion more safely used  as insecticide over that of DDT or Aldrin ?  1
13.  Which of the following is paramagnetic ?
(a) 02- (b) CN- (c) CO (d) NO+		 1
14.  In an ionic crystal, due to nonstoichiometric  Imperfection, there is a coloured centre at
which electron is trapped at anion vacancy. Such a centre is called –
 (a) M ,(b) R, (c) V, (d) F.		 1
15. Choose the ester from the following :
(a) H-CO-CH3 (b) CH3-COOH
(c) C-COO CH3 (d) CH3-COONa.		 1
16.

 The mass of an object changes from 2X10-3g to 2.5XIO-2 g in a time period  of I500 years. The half life of the subject is:
a)500 years (b) 700 years (c) I,000 years (d) 250 years.

  1
17. The expression of the first law of thermodynamics for a process in  which no heat is trans- ferred to and  from the system is (symbols have the usual significances);
(a) q=dE+w (b) dE+w=0
(c) q=w (d) q = E.		 1
18.  Draw a neat and labeled diagram of  the unit cell of Cs Cl type of structure of Na Cl crystal at high pressure.  2
19.  The equilibrium constant of a reversible  reaction is 2X10-7 at 298 K. Calculate the value of ∆Go and predict the  possibility of the reaction.
[Given : R=8,3 JK-l mol-1 ]		 2
20.  Explain :
(a) the primary process of a photochemical  chain reaction
and (b) the photosensitization of a Photosensitised reaction. 		2
21. On the basis of resonance. explain why C6H5  is more acidic than C2H5OH. Give the canonical forms wherever possible. 2
22.  What is lanthanide contraction ? What are the factors responsible for it ?  2
23.

 Give the IUPAC name of the ionization  isomers of the complex compounds exhibited by FeBrSO4. 5NH3. Which of them will be precipitated with BaCI2 solution ?

   2
24.  Draw a neat and labelled apparatus for the electroosmosis.  2
25.  What is a polyamide ? How is nylon-66 synthesised ?  2
26.

 Write the structural formula of the nucleoside containing the base adenine and the sugar deoxyribose. How does he phosphate group attached to this nucleoside ?

2
27.  What is the role of air in respiration ?  How does oxygen be transported in the tissues ?  2
28.

 What is an atomic orbital ? How are its shapes described by azimuthal  quantum number ? State the exclusion  principle as given by Pauli in connection with the distribution of electrons
 in the atomic orbitals.

 3
29.

Given E0 [1/2 Br2/Br-] =+1.08V and E 0 [Fe+3/Fe+2] =+0.77V.
Construct an electrochemical cell using the given electrodes and a salt bridge. Write the overall reaction and Nernst equation of the cell.

 3 
30.

 What are haloalkanes ? Give reactions of one general method of preparation and one synthetic use of it.

3
31. What happens when
(a) acetone reacts with hydroxylamine ?
(b) ocetic anhydride is treated with concentrated ammonia solution at ordinary temperature ?
(c) benzoic acide is treated with thionyl chloride ?		  3
32.  Explain the following :
(a) Chromyl chloride test.
(b) Oxidising action of KMnO4 on acidified FeSO4 solution.
(c) Nonconsideration of Zn, Cd and Hg as transition elements. 		3
33.

 AI(27) undergoes a (n, α) reaction  forming a radio element which decays spontaneously and forms Mg (24). What is the radio ray produced on the spontaneous decay ? Identify M and N in the nuclear reactions :
(i) 227 89 Ac--.>.M+5+5α+3β
and (ii)235 92 U+10 n--.>9742 Mo+210 n+N.

 3
34.

 What are p. block elements ? Name the elements of group17. Which  of them is naturally radioactive ? How would you explain for the higher oxidation states of halogens. except for fluorine ?

 5
35.

 Write the structure of the organic  compounds A to E given in the reactions
A HNO3 (conc) /H2SO4(conc)→B Sn/HCI warm →C NaN02/HCL→OoC→ DCu2/HCL→E+N2.
C is an aromatic compound having the molecular formula C6H7N and gives an offensive swell
when warmed with chloroform and alcoholic  potassium hydroxide

 5
36.

 Explain, why is the vapour pressure of a solution lower than that of the solvent Write the mathematical expression of Raoult’s law of relative lowering of vapour pressure and from this expression how is the molar mass of an electrolytic solute obtained.

 5

 


Council of Higher SecondaryEducation, Manipur

HIGHER SECONDARY EXAMINATION 1999

CHEMISTRY : (THEORY)

Full Marks-70

MARKII\IG SCHEME/SCORING KEY/INSTRUCTION TO EXAMINERS

1. Statement of Hess’s law of constant heat of summation. 1

2. B describes the shorter wave length. 1

=h/p

3. Unit of equivalent conductance given is wrongand therefore, full marks will be awarded to all. 1

4. Definition of activation energy. 1

5. Zero order. [rate is independent of concentration 1

6. CH3C COOH . H

7. Any double salt e.g. FeSO4 (NH4 ) 2 SO4.6H2O. 1

8. Finely divided Powdered catalyst has more surface area and hence more active sites.

9. -CH2-CH-Cl

10. The C-O-C linkage between two components of an acetal is the glycoside linkage. 1

11. Pheromones are the insect/some animal hormones which are principal means of communication among themselves. 1

12. Malathion is biodegradable while DDT and Aldrin are eot biodegradable. Hence malathion is more safely used.

13. (a) O2- 1

14. (d) F 1

15. (c) HCOOCH3

16. (a) 500 years. 1

17. (b) dE+w=0 1

18. B.C.C. with Na+ at the centre of the cube.Drawing........................................... Labelling.......................................

No mark should be awarded for drawing if laballing is wrong.

19. AGO = - 2.303 RT log K.=-2.303x8.3 (JK-l mol-1) x 298 (K) x log 2 x 10-7 =38.159 (KJ mol-1) Correct formula 1
Correct calculation 1

20. (a) It is a process of photochemical reaction inwhich one of the reactants absorb a photon from the light forming reactive species. 1

b) photosensitization is the process of activation of a reactant which itself is not photoactive, but do so by absorbing lightenergy via a foreign photoactive substance and proceeds the reaction. 1 2

21. C6H5OH or -OH Ionised as- CH -O(-)+H(+) Whereas C2H5OH does not. It is because of fact that C2H5O(-) is not stabilised by resonance while 0(-) ion is stabilisen by resonance as follows : 2

22. Lanthanide contraction, statement. 1Any two factors at minimum. 1/2x2

23. (i) Pentaamminebromoiron (11) sulphate 1/2

(ii) Pentaamminesulphatoiron (11) bromide 1/2

The former will be precipitated with BaC1 2solution. 1 2

24. Outline diagram of any design of the apparatusof electro-osmosis 1 Labelling 1 2

25. Definition of Polyamide. 1

Synthesis of nylon - 66 (may be in words or reaction or both) 1

26.C)Adenosine (nucleoside) 11/2Phosphate group is attached to C5 or C3 of thedeoxyribose part of the nucleoside. 1/2

27. The oxygen of air inhaled in respiration is used as oxidant in the biological processes. 1Oxygen taken by the body through lungs is carried to the tissues by blood. 1 2

28.Definition of atomic orbital. 1

The azimuthal quantum number is related to the angular momentum of the electron. Thus it icads to the different shapes of the orbitals. 1Statement of Pauli’s exclusion principle. 1

29. (i) Pt | Fe+2 (aq).Fe+3 (aq)| Br-(aq) | ½ Br2 (aq)| pt. 1

(ii) Fe +2 (aq)+1/2Br2(aq)= Fe+3(aq)+Br-(aq) 1

(iii) E cell=EO cell-2:@@

11log [F (aa). [Br-(aq)j [Fe (.q)][Br2)aq)]vlWhere E0cell=(]. 1 7) & n - 1.

30. Haloalkanes are the halogen derivatives of alkanes. 1

Any method of preparation 1

Any synthetic use 1 3

31. (a) CH3>C=O+H2N-OH--.>. CH,, > C -N-OH+H,10CHS CH3

(b) CH " CO <O+NI-I3-->CH3CONH,+CHaCOONH4 CH3C0

(C) C6 H 5 CO OH + SOCI2 C6H5 COCI +SO2 + HCI. 1+1+1 3

32. (a) K2cr207 +4Nacl+6 conc. H2SO42KHSO4+2cr O2Cl2+4NaHSO4+ 3H2O. NaC1 may be replaced by any other chloride. Orange red vapours ofCro2C12 shows the presence of chloride ion. 1

(b) 2KMnO4+8H2SO4+10 FeSO4 K5SO4+2 MnSO4+5Fe2(SO4)3+8H2O 1

(c) Due to the presence of completly filled inner d- orbital. 3

33. P-ray207

(i) M is pb 182

136(ii) N is Sn

50 1 3

34. Elements having electronic configuration ns2np1-6 are P-block elements. Or, any other suitable statement may be given. 1

Elements of group 17: F, C1, Br, I, At. 1

At. is naturally radioactive 1

Suitable explanation. 2 5

35. A- (benzene) 1

B- NO2 (nitrobenzene) 1

C- NH2 (aniline) 1

D- N=N+CI(benzene diazonium chloride) 1

E- CI (chlorobenzene) 1 5

35. Lowering of V.P. : Suitable explanation. 1

Raoult’s law : L p /PO=X2

where X2 is the mol-fraction of the solute. 1

Deduction of W2yMI

M2 = EP for very dilute solution.WI Ml=molar mass of solvent M2=molar mass of soluteW2=mass of solvent in gramW2=mass of solute in gram. 3 5

Sd/ Head Examiner