A $2 \mathrm{mol}$, equimolar mixture of ${\mathrm{Na}}_2{\mathrm{C}}_2{\mathrm{O}}_4$ and ${\mathrm{H}}_2{\mathrm{C}}_2{\mathrm{O}}_4$ required ${\mathrm{V}}_1 \mathrm{L}$ of $0.1 \mathrm{M} {\mathrm{KMnO}}_4$ in an acidic medium for complete oxidation. The same amount of the mixture required ${\mathrm{V}}_2 \mathrm{L}$ of $0.1 \mathrm{M} \mathrm{NaOH}$. The ratio ${\mathrm{V}}_1:{\mathrm{V}}_2$ is

When $\mathrm{ZnS}$ is boiled with strong nitric acid, the products are zinc nitrate, sulphuric acid and nitrogen dioxide. What are the changes in the oxidation numbers of $\mathrm{Zn},\mathrm{S}$ and $\mathrm{N}$:

${\mathrm{CN}}^{-}$ 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?

Which of the following solutions will exactly oxidize $25 \mathrm{mL}$ of an acid solution of $0.1 \mathrm{M}$ iron$\left(\mathrm{II}\right)$ oxalate?