Question

Oxidation number of H in NaH, CaH$_2$, and LiH, respectively is:

• A. +1, +1, -1
• B. -1, +1, +1
• C. +1, +1, +1
• D. -1, -1, -1

Hint:

In metal hydrides (e.g., NaH, CaH$_2$, LiH), hydrogen acts as a hydride ion (\( H^- \)) with an oxidation number of \(-1\). This is different from most other compounds, where hydrogen typically has an oxidation number of \(+1\).