Complete the following reactions :

(b) Give simple chemical tests to distinguish between the following pairs of compounds :
(i) Ethanal and Propanal
(ii) Benzoic acid and Phenol

Explanation

(a) (i) It is an example of Cannizoro reaction.
(ii) It is an example of Hell-Volhard-Zelinsky reaction.

(b) (i) Test between ethanol and propanal :
Iodoform Test -Ethanal gives iodoform test.
`CH_3CHO+4NaOH+3I_2toCHI_3+HCOONa+3NaI+3H_2O`
Propanal does not gives this test
`CH_3CH_2CHO+4NaOH+3I_2to"No reaction"`
(ii) Test between Benzoic acid and Phenol :
`NaHCO_3` Test : When Benzoic acid reacts with `NaHCO_3`, brisk effervescence of `CO_2`gas evolved.
Phenol does not give this test.