AIIMS 2018 Chemistry Oxidation States MCQ Question

Thorium (Th) typically exhibits a +4 oxidation state, in addition to the +3 state, due to its ability to lose different numbers of electrons from its outer shell. While the +3 state is common, it is inaccurate to state that thorium shows no other variable oxidation states, as it can also form compounds in the +4 state, such as ThO₂. Therefore, option C is correct because the statement in the question is misleading and does not fully capture the oxidation behavior of thorium. Options A and B are incorrect as they misrepresent the oxidation states of thorium, and option D does not apply since the statement can be evaluated.