Question

Aqueous solution of chloride of an element $A$ containing $1 \times 0^{-3} mol$ after complete hydrolysis required $30 \,mL$ of $0.1\, M\, AgNO _3$ solution to form $AgCl$. Element $A$ is (Molar mass $=133.5 \,g \,mol ^{-1}$ )

• A. $Al$
• B. $P$
• C. $Si$
• D. $S$

Answer 1

Answer: (A)

$ACl _n+n H _2 O \rightarrow A ( OH )_n+n HCl$
$n HCl +n AgNO _3 \rightarrow n AgCl +n HNO _3$

But $AgNO _3$ required $=30 \,mL$ of $0.1 \,M$
$=\frac{30 \times 0.1}{1000}=3 \times 10^{-3} mol$
Thus, $1 \times 10^{-3} n=3 \times 10^{-3}$
$\therefore n=3$
Thus, chloride is $ACl _3$
$A+3 \times 35.5=133.5$
$A=27$
Thus, $A$ is $Al$