Question

Aqueous solution of $AlC{l}_3$ is acidic towards litmus while of $NaCl$ is not. The correct reason behind this is:

• A. $AlC{l}_3$ furnishes $O{H}^{-}$ ion in the solution
• B. $AlC{l}_3$ furnishes $H^{+}$ ion in the solution
• C. $AlC{l}_3$ furnishes both $H^{+}$ well as $O{H}^{-}$ ion in the solution
• D. $AlC{l}_3$ is the salt of strong base and strong acid

Answer 1

Answer: (B)

$AlC{l}_3$ furnishes $H^{+}$ ion in the solution

$AlC{l}_3$ is the salt of weak base and strong acid which renders $H^{+}$ ions on hydrolysis. Thus, aqueous solution of $AlC{l}_3$ is acidic in nature.

$A{l}^{3+}+3H_{2}O\rightleftharpoons Al(OH{)}_3+3H^{+}$

On the other hand, $NaCl$ is the salt of strong acid and strong base which does not undergo hydrolysis.