Question

(a) Write the products formed when CH₃CHO reacts with the following reagents:

(i) HCN.
(ii) H₂N – OH
(iii) CH₃CHO in the presence of dilute NaOH

(b) Give simple chemical tests to distinguish between the following pairs of compounds:

(i) Benzoic acid and Phenol
(ii) Propanal and Propanone.

Answer 1

(a)

(i)

(ii)

(iii)

(b)

(i) Benzoic acid and Phenol: On addition of NaHCO₃ to both solutions, carbondioxide gas is evolved with benzoic acid while phenol does not form CO₂.

(ii) Propanal and Propanone: Propanal gives positive test with Fehling solution in which a red ppt. of cuprous oxide is obtained while propanone does not respond to test.