Question

Assertion : A solution of $NH_4C$ in water is acidic in nature.
Reason : Ammonium ions undergo hydrolysis to form $NH_4OH$.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

$NH_4Cl_{(aq)} \to NH+_{4(aq)} +Cl^{-}_{(aq)}$
$NH^+_4$ ions formed, undergo hydrolysis with water to form $NH_4OH$ and $H^+$ ions. $NH_4OH$ is a weak base and thus remains almost unionised in solution. As a result, $[H^+]$ ions increase in solution, making the solution acidic.