A mixture containing ${\mathrm{As}}_2{\mathrm{O}}_3$and ${\mathrm{As}}_2{\mathrm{O}}_5$ required $20 \mathrm{mL} \mathrm{of} 0.05\mathrm{N}$ iodine solution for titration. The resulting solution is then acidified and excess of $\mathrm{Kl}$ was added. The liberated iodine required $1.116 \mathrm{g}$ hypo (${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3.5{\mathrm{H}}_2\mathrm{O}$) for complete reaction. Calculate the mass of the mixture. The reactions are:

$$\begin{gathered} {\mathrm{As}}_2{\mathrm{O}}_3 + 2{\mathrm{I}}_2 + 2{\mathrm{H}}_2\mathrm{O} \stackrel{}{\to } {\mathrm{As}}_2{\mathrm{O}}_5 + 4{\mathrm{H}}^{+}+4{\mathrm{I}}^{-} \\ {\mathrm{As}}_2{\mathrm{O}}_5 + 4{\mathrm{H}}^{+}+ 4{\mathrm{I}}^{–} \stackrel{}{\to } {\mathrm{As}}_2{\mathrm{O}}_3+ 2{\mathrm{I}}_2 + 2{\mathrm{H}}_2\mathrm{O} \end{gathered}$$

(Atomic weight: $\mathrm{As} = 75$)

A $100 \mathrm{mL}$ sample of water was treated to convert any iron present to ${\mathrm{Fe}}^{2+}$. Addition of $25 \mathrm{mL} \mathrm{of} 0.002 \mathrm{M} {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ resulted in the reaction:

$6{\mathrm{Fe}}^{2+} + {\mathrm{Cr}}_2{\mathrm{O}}_7{ }^{2–} + 14{\mathrm{H}}^{+} \stackrel{}{\to } 6{\mathrm{Fe}}^{3+} + 2{\mathrm{Cr}}^{3+} + 7{\mathrm{H}}_2\mathrm{O}$

The excess ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ was back-titrated with $7.5 \mathrm{mL} \mathrm{of} 0.01 \mathrm{M} {\mathrm{Fe}}^{2+}$ solution. Calculate the parts per million $\left(\mathrm{ppm}\right)$ of iron in the water sample.

$3 \mathrm{g}$ of an oxide of a metal is converted to chloride completely and it yielded $5 \mathrm{g}$ of chloride. Equivalent weight of the metal is:

An ion is reduced to the element when it absorbs $6\times {10}^{20}$ electrons. The number of equivalents of the ion is

When ${\mathrm{N}}_2$ is converted into ${\mathrm{NH}}_3$, the equivalent weight of nitrogen will be

In the ionic equation $2{\mathrm{K}}^{+}{{\mathrm{BrO}}_3}^{{}^{–}}+12{\mathrm{H}}^{+}+10{\mathrm{e}}^{–}\to {\mathrm{Br}}_2+6{\mathrm{H}}_2\mathrm{O}+2{\mathrm{K}}^{+}$, the equivalent weight of ${\mathrm{KBrO}}_3$ will be

$(\mathrm{Where}, \mathrm{M}=\mathrm{molecular} \mathrm{weight} \mathrm{of} {\mathrm{KBrO}}_3)$

If one mole of ${\mathrm{H}}_2{\mathrm{SO}}_{4 }$ reacts with one mole of $\mathrm{NaOH}$, the equivalent weight of ${\mathrm{H}}_2{\mathrm{SO}}_4$ will be

If equal volumes of $0.1\mathrm{M} {\mathrm{KMnO}}_4$ and $0.1\mathrm{M} {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ solutions are allowed to oxidise ${\mathrm{Fe}}^{2+}$ to ${\mathrm{Fe}}^{3+}$ in an acidic medium, then the ${\mathrm{Fe}}^{2+}$ oxidised will be

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?