Question

Write chemical equations for obtaining carboxylic acid from the following:

Hint:

When working with Grignard reagents, always ensure that they are handled under anhydrous conditions to prevent hydrolysis.

Answer 1

(A) Toluene:
Toluene can be oxidized to benzoic acid using potassium permanganate: \[ \text{C}_6\text{H}_5\text{CH}_3 + 2\text{KMnO}_4 + 2\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_5\text{COOH} + 2\text{MnO}_2 + 2\text{KOH} \] (B) Ethane nitrile:
Ethane nitrile (ethyl cyanide) can be hydrolyzed to acetic acid: \[ \text{CH}_3\text{CN} + 2\text{H}_2\text{O} \xrightarrow{\text{H}^+} \text{CH}_3\text{COOH} \] (C) Ethanamide:
Ethanamide can be hydrolyzed to acetic acid under acidic conditions: \[ \text{CH}_3\text{CONH}_2 + 2\text{H}_2\text{O} \xrightarrow{\text{H}^+} \text{CH}_3\text{COOH} + \text{NH}_3 \] (D) RMgX:
Grignard reagents (RMgX) can react with carbon dioxide to form carboxylic acids: \[ \text{RMgX} + \text{CO}_2 \xrightarrow{\text{H}^+} \text{RCOOH} \] v) Benzoic anhydride:
Benzoic anhydride can be hydrolyzed to benzoic acid: \[ \text{C}_6\text{H}_5\text{CO}_2\text{CO}\text{C}_6\text{H}_5 + \text{H}_2\text{O} \rightarrow 2\text{C}_6\text{H}_5\text{COOH} \] Final Answer: (A) Toluene → Benzoic acid with potassium permanganate
(B) Ethane nitrile → Acetic acid with water and acid
(C) Ethanamide → Acetic acid with water and acid
(D) RMgX → Carboxylic acid with CO₂
v) Benzoic anhydride → Benzoic acid with water Correct Answer: Equations for each reaction are shown above.