Question

A mixture of Benzaldehyde and Formaldehyde on heating with $ NaOH $ solution gives:
A) Benzyl alcohol and Sodium formate
B) Sodium benzoate and Methyl alcohol
C) Sodium benzoate and Sodium formate
D) Benzyl alcohol and Methyl alcohol

Answer 1

Hint: The treatment of two Aldehydes which do not contain $ \alpha $ hydrogen atoms undergo redox reaction. One molecule of aldehyde undergoes reduction to form alcohol and another molecule of aldehyde undergoes oxidation to form sodium salt of carboxylic acid in presence of a base.

Complete answer:
Organic reactions are of different types. Cannizzaro reaction is one of the organic reactions in which the two molecules of aldehydes that do not contain $ \alpha $ hydrogen atoms undergo redox or disproportion reaction. Disproportion reaction is a reaction in which one molecule of aldehyde undergoes reduction to form alcohol and another molecule of aldehyde undergoes oxidation to form sodium salt of carboxylic acid in presence of a base or alkali solution like sodium hydroxide $ \left( {NaOH} \right) $.
Given two molecules of Aldehyde are Benzaldehyde and Formaldehyde. On treating this mixture with Sodium hydroxide $ \left( {NaOH} \right) $ solution, Benzaldehyde $(C_6H_5CHO)$ undergoes reduction to form Benzyl alcohol $(C_6H_5CH_2OH$ and Formaldehyde $(HCHO)$ undergoes oxidation to form Sodium salt of Carboxylic acid.
 $ {C_6}{H_5}CHO + HCHO\xrightarrow{{NaOH}}{C_6}{H_5}C{H_2}OH + HCOONa $
Thus, the products are Benzyl alcohol$(C_6H_5CH_2OH$ and Sodium Formate$(HCOONa)$. So, Option (A) is the correct option.

Note:
When two molecules of same aldehyde are taken then the products are alcohol and sodium salt of carboxylic acid. In the above reaction the two molecules are different as the addition of hydroxide ion on the formaldehyde is faster, it leads to the formation of carboxylic acid salt.