The oxidation number of in is: — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

$K_3CrO_8$ is a tetraperoxo complex $[Cr(O_2)_4]^{3-}$. $Cr$ is $+5$ and 4 peroxo groups are each $-2$ (total $-8$). $+5 + (-8) = -3$. [1, 7]