0.1 g of metal combines with 46.6 mL of oxygen at STP. The equivalent weight of metal is

1 mol of O₂ = 4 eq.of O

22400 mL of O₂ = 4 eq. of O

46.6 mL of O₂ = $\frac{4}{22400}\times 46.6=0.00832 \mathrm{eq}$

Equivalent of metal = Equivalent of O

$\frac{\mathrm{Weight}}{\mathrm{Ew}}=0.00832$

$$\begin{gathered} \frac{0.1}{\mathrm{E}}=0.00832 \\ \therefore \mathrm{E}=\frac{0.1}{0.00832}=12.0 \end{gathered}$$