RE-NEET 2026 Chemistry Oxidation States MCQ Question

The correct decreasing order of oxidation states is determined by calculating the oxidation state of the underlined atoms in each compound.

For option A:

• In $N_2O_5$, nitrogen has an oxidation state of +5.
• In $Al_2O_3$, aluminum has an oxidation state of +3.
• In $H_2S$, sulfur has an oxidation state of -2.

Thus, the order is +5 (N) > +3 (Al) > -2 (S).

The other options fail because their calculated oxidation states do not align in a decreasing order. For instance, in option B, lead in $PbO_2$ has an oxidation state of +4, which does not fit the required order compared to nitrogen in $N_2O_3$.