Question

a carbon compound X turns blue litmus to red and has a molecular formula C2 H4 O2 . identify X and draw its structure

Answer 1

It is acetic acid. it is carboxylic acid

Answer 2

Answer: $CH_3COOH$

Explanation: Acids are substances which gives $H^+$ ions when dissolved in water and turns blue litmus red.

Thus carbon compound which turns blue litmus red should be an acid and must be a carboxylic acid with functional group -COOH and thus the reamining substituent is $CH_3$

$CH_3COOH(aq)\rightarrow CH_3COO^-(aq)+H^+(aq)$