CBSE Class 12 Chemistry 2016 Delhi Set 1 Solved Paper

Question : 25

Total: 26

Write the structures of A, B, C, D and E in the following reactions:

OR
(a) Write the chemical equation for the reaction involved in Cannizzaro reaction.
(b) Draw the structure of the semicarbazone of ethanal.
(c) Why pKa of F−CH2−COOH is lower than that of Cl−CH2−COOH ?
(d) Write the product in the following reaction
(e) How can you distinguish between propanal and propanone?

Solution:

OR
(a) 2‌HCHO‌ ‌

50% ‌NaOH

─────▸

‌CH3‌OH+HCOONa
(b) CH3−CH=N−NH−CO−NH2
(c) In FCH2−COOH, fluorine is more electron withdrawing than chlorine in ClCH2−COOH, so FCH2−COOH, flurine is more acidic than ClCH2‌COOH hence its pKa value is lesser than ClCH2‌COOH.
(c)

CH3−CH=CH−CH2−CN

Pent−3−enenitrile

‌

‌ (i) ‌DIBL−H

─────▸

‌ (i) ‌H2O

CH3−CH=CH−CH2−CHO

Pent−3−ene−1−al

(e) Propanal and propanone can be differentiated by Tollens' reagent i.e., propanal will give silver mirror but propanone will not.
CH3−CH2−CHO+2[Ag(NH3)2]+→CH3−CH2 −COO−+2‌Ag +

H2O+4NH3

Silver‌mirror

Go to Question:

Prev Question

Next Question