SAMPLE PAPER (2023 -24)
CHEMISTRY THEORY (043)
MARKING SCHEME
SECTION A
1. (b) 0.1 M HCl solution, conductivity is higher for strong electrolyte, conductivity decreases with
dilution
2. (c) A= Benzaldehyde , B= Acetophenone. This is an example of crossed Aldol condensation.
3. (d) Vitamin A,D, E and K These are fat soluble vitamins
4. (a) 3-Methylpent-3-en-2-one
5. (b) The carbon-magnesium bond is covalent and non-polar in nature .
6. (a) (i) (r) , (ii) (q), (iii) (p)
Zinc has no unpaired electrons in 3d or 4s orbitals, so enthalpy of atomization is low
Mn = 3d54s2 shows +2,+3,+4,+5,+6 and+7 oxidation state , maximum number in 3d series
7. (b) molecularity has no meaning for complex reactions.
8. (c) water
9. (b) no turbidity will be observed, given compound is a primary alcohol
10. (a) 0.00625 molL-1s-1 for zero order k = [Ro] –[R] / t = 1.5 -0.75 /120
11. (a) Due to the activation of benzene ring by the methoxy group.
12. (b) atomic radii
for visually challenged learners
12. (d) Zinc
13. (c) A is true but R is false
14. (b) Both A and R are true but R is not the correct explanation of A
15. (b) Both A and R are true and R is not the correct explanation of A.
16. (d) A is false but R is true.
Cu will deposit at cathode
SECTION B
17. (a) for first order reaction
half life of X = 12 hours
2 days = 48 hours means 4 half lives , amount of X left = 1/16 of initial value
half life of Y = 16 hours ( ½)
2 days = 48 hours means 3 half lives, amount left = 1/8 of initial value
Ratio of X:Y = 1:2 ( ½)
(b) b. mol1/2L-1/2s-1 as Rate = k [P]1/2 (1)
18. π1 = π2 (1/2)
iC1RT = C2RT (1/2)
, 3 5 2
(1/2)
322 M
2 322
M (1/2)
3 5
M = 42.9 g
19. (a) m-dicholrobenzene < o-dicholrobenzene < p-dicholrobenze (1/2)
symmetrical structure and close packing in para isomer
ortho has a stronger dipole dipole interaction as compared to meta (1/2)
(b) the halogen atom because of its –I effect has some tendency to withdraw electrons from the
benzene ring. As a result, the ring gets somewhat deactivated as compared to benzene and hence
the electrophilic substitution reactions in haloarenes occur slowly and require more drastic
conditions as compared to those in benzene. (1)
20. (a) p-nitrobenzaldehyde is more reactive towards the nucleophilic addition reaction than p-
tolualdehyde as Nitro group is electron withdrawing in nature . Presence of nitro group decrease
electron density, hence facilitates the attack of nucleophile . Presence of -CH 3 leads to +I effect as -
CH 3 is electron releasing group. (1)
(b)
( (1)
OR
(a)
(1)
(b)
(1)
21. (a) Replication
A sequence of bases on DNA is unique for a person and is the genetic material transferred to the
individual from the parent which helps in the determination of paternity. (1)
CHEMISTRY THEORY (043)
MARKING SCHEME
SECTION A
1. (b) 0.1 M HCl solution, conductivity is higher for strong electrolyte, conductivity decreases with
dilution
2. (c) A= Benzaldehyde , B= Acetophenone. This is an example of crossed Aldol condensation.
3. (d) Vitamin A,D, E and K These are fat soluble vitamins
4. (a) 3-Methylpent-3-en-2-one
5. (b) The carbon-magnesium bond is covalent and non-polar in nature .
6. (a) (i) (r) , (ii) (q), (iii) (p)
Zinc has no unpaired electrons in 3d or 4s orbitals, so enthalpy of atomization is low
Mn = 3d54s2 shows +2,+3,+4,+5,+6 and+7 oxidation state , maximum number in 3d series
7. (b) molecularity has no meaning for complex reactions.
8. (c) water
9. (b) no turbidity will be observed, given compound is a primary alcohol
10. (a) 0.00625 molL-1s-1 for zero order k = [Ro] –[R] / t = 1.5 -0.75 /120
11. (a) Due to the activation of benzene ring by the methoxy group.
12. (b) atomic radii
for visually challenged learners
12. (d) Zinc
13. (c) A is true but R is false
14. (b) Both A and R are true but R is not the correct explanation of A
15. (b) Both A and R are true and R is not the correct explanation of A.
16. (d) A is false but R is true.
Cu will deposit at cathode
SECTION B
17. (a) for first order reaction
half life of X = 12 hours
2 days = 48 hours means 4 half lives , amount of X left = 1/16 of initial value
half life of Y = 16 hours ( ½)
2 days = 48 hours means 3 half lives, amount left = 1/8 of initial value
Ratio of X:Y = 1:2 ( ½)
(b) b. mol1/2L-1/2s-1 as Rate = k [P]1/2 (1)
18. π1 = π2 (1/2)
iC1RT = C2RT (1/2)
, 3 5 2
(1/2)
322 M
2 322
M (1/2)
3 5
M = 42.9 g
19. (a) m-dicholrobenzene < o-dicholrobenzene < p-dicholrobenze (1/2)
symmetrical structure and close packing in para isomer
ortho has a stronger dipole dipole interaction as compared to meta (1/2)
(b) the halogen atom because of its –I effect has some tendency to withdraw electrons from the
benzene ring. As a result, the ring gets somewhat deactivated as compared to benzene and hence
the electrophilic substitution reactions in haloarenes occur slowly and require more drastic
conditions as compared to those in benzene. (1)
20. (a) p-nitrobenzaldehyde is more reactive towards the nucleophilic addition reaction than p-
tolualdehyde as Nitro group is electron withdrawing in nature . Presence of nitro group decrease
electron density, hence facilitates the attack of nucleophile . Presence of -CH 3 leads to +I effect as -
CH 3 is electron releasing group. (1)
(b)
( (1)
OR
(a)
(1)
(b)
(1)
21. (a) Replication
A sequence of bases on DNA is unique for a person and is the genetic material transferred to the
individual from the parent which helps in the determination of paternity. (1)
