Question

Aqueous solution of chloride of an element $A$ containing $1\times {10}^{-3}$ moles after complete hydrolysis required $30$ mL of $0.1$ M $AgN{O}_3$ solution to form $AgCl$. Element $A$ is :

• A. Al
• B. P
• C. Si
• D. S

Answer 1

Answer: (A)

Al

$MC{l}_n(1\times {10}^{-3})+3H_{2}O\to M(OH{)}_n+nHCl(n\times {10}^{-3})$
$30$ mL of $0.1$ M $A{g}^{+}=3\times {10}^{-3}molA{g}^{+}$ $=n\times {10}^{-3}$.
$n=3$, thus element $A$ is trivalent chloride $AlC{l}_3$.