Question

The hydride ion, $H^-$, is a stronger base than the hydroxide ion, $OH^-$. Which one of the following reactions will occur if sodium hydride ($NaH$) is dissolved in water?

• A. $H^-_{(aq)} + H_2O (l)\rightarrow OH^-(aq) + 2H_2(g)$
• B. $H^-(aq) + H_2O(l) \rightarrow H_3O^-(aq)$
• C. $H^-(aq) + H_2O (l)\rightarrow OH^-{(aq)} + 2H^+(aq) + 2e$
• D. $H^-(aq) + H_2O (l) \rightarrow$ No reaction

Answer 1

Answer: (A)

$\underset{base 1}{H^-(aq)} + \underset{acid 1 }{H_2O(l)} \rightarrow \underset{base 2 }{OH^-(aq)} + \underset{acid 2}{H_2(g)}$
In this reaction $H^-$ acts as Bronsted base as it accepts one proton $(H^+)$ from $H_2O$ and for $H_2$.