The resonating structures of the cyanate ion are . The correct set of the oxidisation states of $\mathrm{O}, \mathrm{C} \& \mathrm{N}$, respectively, with the most stable structure out of the above is:

${\mathrm{CN}}^{-}$ is oxidised by ${\mathrm{NO}}_3^{-}$ in the presence of an acid : ${\mathrm{aCN}}^{-}+{\mathrm{bNO}}_3^{-}+{\mathrm{cH}}^{+}⟶\left(\mathrm{a}+\mathrm{b}\right)\mathrm{NO}+{\mathrm{aCO}}_2+\frac{\mathrm{c}}{2}{\mathrm{H}}_2\mathrm{O}$. What are the whole number values of $\mathrm{a}, \mathrm{b}, \mathrm{c}$ in that order?

The number of moles of ${\mathrm{KMnO}}_4$ that will be needed to react completely with one mole of ferrous oxalate in an acidic solution is:

$2 \mathrm{litres}$ of ammonia at $13 °\mathrm{C}$ and $0.90$ atmospheric pressure is neutralised by $134 \mathrm{ml}$ of ${\mathrm{H}}_2{\mathrm{SO}}_4$ solution. Find the normality of the acid.

Give the answer after rounding-off to two places of decimal.