Question

Choose the correct option regarding change in oxidation number of the underlined atom in the following conversion.

$\underset{–}{A{s}_2}{S}_3+O{H}^{-}\to As{S}_4^{3-}$

Answer 1

In the transformation, $\underset{–}{A{s}_2}{S}_3+O{H}^{-}\to As{S}_4^{3-}$, the oxidation number of $As$ changes from $+3$ to $+5$.
Hence, the change in the oxidation number of $As$ is $2$.