Chemistry Carboxylic Acids MDCAT 2010
PMDC Verified Question 93 of 94
Hydrolysis of cyano group by an aqueous acid results into:
A
Acid amide
B
Cyano hydride
C
Carboxylic acid
D
Formaldehyde
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Carboxylic acid
Concept:

The acidic hydrolysis of an alkyl cyanide (nitrile group) completely converts the cyano group into a carboxyl group.

Formula:

$$ \text{R-C}\equiv\text{N} + 2\text{H}_2\text{O} + \text{HCl} \longrightarrow \text{R-COOH} + \text{NH}_4\text{Cl} $$

Solution:

  • When boiled with an aqueous mineral acid, the triple bond of the cyano group breaks.


  • The nitrogen atom picks up protons to form an ammonium salt.


  • The carbon atom oxidizes to form a carboxylic acid.


Why other options are incorrect:

Acid amides are intermediate products of partial hydrolysis. Cyano hydrides and formaldehyde are structurally unrelated to the hydrolysis of nitriles.

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