For the decolourization of $1 \ mole$ of $KMnO_4$,the moles of $H_2O_2$ required is: (in $.5$)

What is the equivalent weight of $IO_4^-$ when it is converted to $I_2$ in an acidic medium?

The reaction,$K_2Cr_2O_7 + m \, FeSO_4 + n \, H_2SO_4 \longrightarrow Cr_2(SO_4)_3 + p \, Fe_2(SO_4)_3 + K_2SO_4 + q \, H_2O$ when balanced,$m, n, p$ and $q$ are,respectively:

In the given reaction,calculate the number of electrons lost by iron:
$3Fe + 4H_2O \to Fe_3O_4 + 4H_2$

Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide. Present a balanced equation for this redox change taking place in water.

$A$ $20.0 \,mL$ solution containing $0.2 \,g$ impure $H_2O_2$ reacts completely with $0.316 \,g$ of $KMnO_4$ in acidic solution. The purity of $H_2O_2$ (in $\%$) is........... (mol. wt. of $H_2O_2 = 34$; mol. wt. of $KMnO_4 = 158$)