Question

The acid present in curd/sour milk is:

• A. Acetic acid
• B. Formic acid
• C. Lactic acid
• D. Hydrochloric acid

Answer 1

The correct option is C

Lactic acid

Acid	Chemical formula	where found and use
Acetic acid	${\mathrm{CH}}_3\mathrm{COOH}$	Found in vinegar, used as solvent in the manufacture of dyes and perfumes.
Formic acid	$\mathrm{HCOOH}$	Found in the stings of ants and bees, used in tanning leather, in medicines for treating gout.
Lactic acid Organic acid	${\mathrm{CH}}_3\mathrm{CH}\left(\mathrm{OH}\right)\mathrm{COOH}$	Responsible for souring of milk in curd.
Hydrochloric acid	HCl	In purification of common salt, in textile industry as bleaching agent, to make aqua regia, in stomach as gastric juice, used in tanning industry

Conclusion Statement: Hence, Option(C) is correct.