Question

When an organic compound of molecular formula \( C_4H_8O_2 \) undergoes hydrolysis with dilute \( H_2SO_4 \), a carboxylic acid A and an alcohol B are obtained. On oxidising B with chromic acid, carboxylic acid A is obtained. On heating A with \( P_2O_5 \), acid anhydride C of this acid is obtained. On hydrolysing this anhydride, acid A is obtained again. Identify A, B, and C and also write chemical equations related to them.

Hint:

Carboxylic acids form anhydrides when heated with dehydrating agents like \( P_2O_5 \), and the process is reversible via hydrolysis.

Answer 1

- Compound \( A \): Ethanoic acid (\( CH_3COOH \)) 
- Compound \( B \): Ethanol (\( CH_3CH_2OH \)) 
- Compound \( C \): Ethanoic anhydride (\( (CH_3CO)_2O \)) 

Chemical equations: 1. Hydrolysis of \( C_4H_8O_2 \) (ethyl acetate): \[ CH_3COOC_2H_5 + H_2O \xrightarrow{H_2SO_4} CH_3COOH + C_2H_5OH \] 2. Oxidation of ethanol (\( B \)): \[ C_2H_5OH + [O] \xrightarrow{H_2CrO_4} CH_3COOH \] 3. Formation of acid anhydride (\( C \)): \[ 2CH_3COOH \xrightarrow{P_2O_5} (CH_3CO)_2O + H_2O \] 4. Hydrolysis of acid anhydride (\( C \)): \[ (CH_3CO)_2O + H_2O \rightarrow 2CH_3COOH \]