Question

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

• A. $2 H ^{-}( aq )+ H _{2} O (l) \longrightarrow H _{2} O + H _{2}+2 e^{-}$
• B. $H ^{-}(a q)+ H _{2} O (l) \rightarrow OH ^{-}+ H _{2}$
• C. $H^-+H_2O(l) \rightarrow$ No reaction
• D. None of the above

Answer 1

Answer: (B)

Sodium hydride dissolved in water as
$NaH + H _{2} O \rightarrow NaOH + H _{2}$
or $H ^{-}(a q)+ H _{2} O ( l ) \rightarrow OH ^{-}+ H _{2} \uparrow$
In the above reaction hydride ion take proton from water molecule and hydrogen gas is evolved.