Calculate normality of a salt solution [of a metal sulphatel having concentration $21.6\mathrm{\%} w/v$ if its superoxide has $16\mathrm{\%}$ by mass of oxygen.

Equivalent weight of superoxide ion, ${\mathrm{O}}_2^{-}=\frac{32}{1}=32$
In superoxide of metal : Equivalent  of  metal = Equivalent  of superoxide ion
$\frac{84}{\mathrm{E}}=\frac{16}{32}$ [E : Equivalent weight of metal]
$\mathrm{E}=168$
Equivalent weight of metal sulphate$=$ Equivalent weight of metal+ Equivalent weight of $S{O}_4^{-2}$
$\mathrm{Equivalent} \mathrm{weight}=168+\frac{96}{2}=168+48=216$
$21.6\%$w/v means $100 \mathrm{ml}$ of solution contains $21.6$ g of metal sulphate:

$\mathrm{Normality}=\frac{\mathrm{equivalent} \mathrm{of} \mathrm{metal} \mathrm{sulphate}}{\mathrm{Volume} \mathrm{of} \mathrm{solution} (\mathrm{in} \mathrm{L})}=\frac{21.6/216}{0.1}=1 \mathrm{N}$