How many moles of $KMn{O}_4$ are required to oxidise one mole of $SnC{l}_2$ in acidic medium ?

The correct option is B $\frac{2}{5}$

Equate equivalents.

Equivalents = $n-factor\times moles$

For $KMn{O}_4$ n-factor is 5. Let moles be 'm'.

So equivalents of $KMn{O}_4=5\times m=5m$.

n-factor for $SnC{l}_2$ is 2 as it goes from $+2-+4$ oxidation state. It's moles is 1.

So equivalents is 2.

$5m=2$

$m=\frac{2}{5}$