Chapter 3, Problem 56E

Hydrogen and oxygen usually have oxidation states of $+1$ and $-2$ , respectively, in their compounds. The following cases serve to remind us that there are exceptions. What are the oxidation states of the atoms in each of the following compounds? $\left(\text{a}\right){\text{ MgH}}_{\text{2}}\text{; }\left(\text{b}\right){\text{ CsO}}_{\text{2}}\text{; }\left(\text{c}\right)\text{ HOF; }\left(\text{d}\right){\text{ NaAIH}}_{\text{4}}\text{.}$