Question

Benzoic acid reacts with $Ca{(OH)_2}$ . The product obtained on dry distillation is:
A.Benzophenone
B.Acetophenone
C.Benzaldehyde
D.None of these

Answer 1

Hint: Basically, dry distillation refers to the heating of solid materials to produce gaseous products. Moreover, benzoic acid is an organic compound with chemical formula ${C_6}{H_5}COOH$ and is said to be an aromatic carboxylic acid.

Complete step by step answer:
Benzoic acid is an organic compound which consists of a carboxyl group attached to a benzene ring. This compound basically exists as a crystalline, colorless solid under normal conditions. It further has a chemical formula ${C_6}{H_5}COOH$ .
Now, this compound is not very soluble in water. However, its solubility increases with an increase in the temperature. The commercial production of this compound is done via partial oxidation of toluene with oxygen which is further catalyzed by manganese or cobalt. Moreover, there is another method which includes the reaction of tri-chlorotoluene. with calcium hydroxide in presence of water and further treating the calcium benzoate product with hydrochloric acid.
Now, when benzoic acid reacts with $Ca{(OH)_2}$ , the following product is formed:
 ${C_6}{H_5}COOH + Ca{(OH)_2} \to {({C_6}{H_5}CO{O^ - })_2}C{a^{2 + }} + {H_2}O$
Further, on dry distillation, it gives benzophenone. The reaction is as shown:
 ${({C_6}{H_5}CO{O^ - })_2}C{a^{2 + }} \to {C_6}{H_5} - CO{C_6}{H_5} + CaO + C{O_2}$
So, as we have seen that the product obtained on dry distillation is benzophenone.

Hence, option A is correct.

Note:
Benzoic acid is used in the production of phenol, in ointments that prevent or treat fungal skin diseases, as a preservative in the food industry and also as a precursor to benzoyl chloride. Moreover, it is also one of the components of toothpaste, mouthwash and face wash creams.