Question

Sodium hydride (\[NaH\]) when dissolved in water produces_____
a.) Acidic solution
b.) basic solution
c.) neutral solution
d.) cannot be predicted

Answer 1

Hint: Sodium hydride is a strong base also called super base. As a base, it deprotonates Bronsted acids and produces sodium derivatives of alcohols, phenols, etc.

Complete answer:
Sodium hydride reacts with water and produces sodium hydroxide. Sodium Hydroxide being a metal hydride is basic in nature and hence, the solution is also basic. In this reaction, sodium hydride deprotonate water, that is, it removes \[{{H}^{+}}\] and forms sodium hydroxide (base).
It releases hydrogen gas as a by-product of the reaction. Hydrogen is a highly flammable gas. The hydrolysis of sodium hydride occurs in the reaction where it gets broken into to Na⁺ Cation and \[{{H}^{-}}\] anion. The \[N{{a}^{+}}\] forms sodium hydroxide and \[{{H}^{-}}\] forms hydrogen gas. The formation of sodium hydroxide reduces the risk of fires. Sodium Hydroxide is corrosive in nature. The reaction takes place as follows:
\[NaH(s)+{{H}_{2}}O(l)\to N{{a}^{+}}(aq.)+{{H}_{2}}(g)\]
The hydrolysis of \[NaH\] is violent. The reaction is an exothermic reaction in which the energy is released. This energy can also cause ignition of flammable hydrogen gas. So, handling should be necessarily done with precautions. Sodium hydride acts as a reducing agent.

The correct answer is (B).

Note: Hydride Ion(\[{{H}^{-}}\]) produced after the hydrolysis of \[NaH\] is quite unstable and vigorously reacts with water to form hydrogen gas. \[{{H}^{-}}\] is a negative monovalent ion. Ammonia is a hydride of nitrogen. Charge on the hydride ion is -1. Water is also a hydride and that of oxygen. Hydride ion is known by its leaving property, that is, it is a leaving group.