Question

In the redox titration using potassium permanganate, the acidification is usually done using $H_{2}S{O}_4$ instead of $HCl$. Why?

• A. $H_{2}S{O}_4$ is stronger acid than $HCl$.
• B. $HCl$ is oxidised by $KMn{O}_4$ to $C{l}_2$.
• C. $H_{2}S{O}_4$ is a dibasic acid.
• D. Only $H_{2}S{O}_4$ is completely ionised.

Answer 1

The correct option is B $HCl$ is oxidised by $KMn{O}_4$ to $C{l}_2$.

Use of $HCl$ is avoided as $KMn{O}_4$ oxidises $HCl$ to $C{l}_2$ gas.
$2KMn{O}_4+16HCl\to 2KCl+2MnC{l}_2+8H_{2}O+5C{l}_2.$
Hence option (b) is correct.