Question

Alkali metal hydrides react with water to give
A. Acidic solution
B. Basic solution
C. Neutral solution
D. Hydride ion

Answer 1

Hint: From a metal from the first group of the s block of the periodic table, alkali metal hydrides are created. This involves a covalent or ionic bond between the metal atom and the hydrogen atom. Usually, when a metal hydride is hydrolyzed, a strong base is formed and hydrogen gas is released.

Complete Step by Step Answer:
All the metal hydrides of group one or we can say that the alkali metal hydrides react very vigorously with the water resulting in the release of a high amount of energy in the form of hydrogen gas along with a very strong base. In the case of a metal hydride, hydrogen dissociates from the metal in the form of hydride ion (${{H}^{-}}$). The reaction of metal hydride with water can be shown below:
\[M{{H}_{\left( s \right)}}+{{H}_{2}}{{O}_{\left( aq \right)}}\to MO{{H}_{\left( aq \right)}}+{{H}_{2\left( g \right)}}\]

Here, we can infer from the reaction that there is the formation of metal hydroxides which are considered as strong bases and there is evolution of hydrogen gas.
Alkali metals include Hydrogen, Lithium, Sodium, Potassium, Rubidium, Caesium, Francium.
Let’s take an example of the reaction of sodium hydride with water,
\[Na{{H}_{(s)}}+{{H}_{2}}{{O}_{(l)}}\to NaO{{H}_{(aq)}}+{{H}_{2(g)}}\]
So, we can see that when sodium hydride reacts with water to give sodium hydroxide and hydrogen gas.
Hence, the correct option is B. Basic solution.

Note: When in contact with water, several metal hydrides react violently due to their high reactivity. As an illustration, sodium hydride is highly reactive. The end product is a highly potent base. To create the metal derivative of alcohols and phenols, it can deprotonate an acid.