Question

Find out the percentage purity of $KMnO_{4}$ if $2g$ impure sample of $KMnO_{4}$ requires $40ml$ of $0.5M$ ferrous oxalate for complete reduction in acidic medium.

• A. $80.5\%$
• B. $56.4\%$
• C. $72.3\%$
• D. $94.8\%$

Answer 1

Answer: (D)

$\frac{w t \, .}{158}\times 5\times 1000=40\times 0.5\times 3$
$wt. \, =1.896$
$\% \, purity=\frac{1.896}{2}\times 100=94.8\%$