Ncert Solutions Chemistry Class 11th

12.44. Assertion: The energy of actual structure of the molecule(the resonance hybrid) is lower than that of anyof the canonical structures.

Reason: Resonance is particularly important when the contributing structures are equivalent in energy.

12.43.Assertion: In homolytic cleavage, the movement of a single electron takes place instead of an electron pair.

Reason: A homolytic cleavage yields carbocations or carbanions.

12.40. The reaction:
CH₃CH₂I + KOH (aq) → CH₃CH₂OH + KI is classified as:
(a) electrophilic substitution (b) nucleophilic substitution
(c) elimination (d) addition

12.39. The best and latest technique for isolation, purification and separation of organic compounds is:

 (a) Crystallisation (b) Distillation(c) Sublimation (d) Chromatography

12.38. Which of the following carbocation is most stable? (Intermediate)

12.37. In Lassaigne's test for nitrogen in an organic compound, the Prussian blue colour is obtained due to the formation of:
(a) Na₄[Fe(CN)₆] (b)Fe₄[Fe(CN)₆]₃
(c) Fe₂[Fe(CN)₆] (d)Fe₃[Fe(CN)₆]₄ . (Intermediate)

12.36. In the organic compound CH2 = CH – CH2 – CH2 – C ≡ CH, the pair of hybridised orbitals involved in the formation of: C2 – C3 bond is:

(a) sp – sp² (b) sp – sp³ (c) sp² – sp³ (d) sp³ – sp³

12.35. In an estimation of sulphur by Carius method, 0.468 of an organic sulphur compound gave 0.668 g of barium sulphate. Find out the percentage of sulphur in the compound.

12.34. 0.3780 g of an organic compound gave 0.5740 g of silver chloride in Carius estimation. Calculate the percentage of chlorine present in the compound.

12.33. A sample of 0.50 g of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in 50 ml of 0.5M H₂SO₄. The residual acid required 60 ml of 0.5 M solution of NaOH for neutralization. Find the percentage composition of nitrogen in the compound.