Question

Write the chemical formula of ammonium chloride. Explain why an aqueous solution of ammonium chloride is acidic in nature? Illustrate your answer with the help of a chemical reaction.

Answer 1

Hint: Ammonium chloride is made up of two ions: ammonium ion and chloride ion. Ammonium chloride is a salt that is formed by strong acid and a weak base.

Complete step by step answer:
Ammonium chloride is made up of two ions: ammonium ion whose formula is $NH_{4}^{+}$ and chloride ion whose formula is $C{{l}^{-}}$. So the chemical formula of ammonium chloride will be $N{{H}_{4}}Cl$.
When we dissolve ammonium chloride in water, the aqueous solution is acidic in nature. This is due to the fact that ammonium chloride is a salt and it is formed by strong acid and a weak base. The strong acid is hydrochloric acid whose formula is $HCl$ and the weak base is ammonium hydroxide whose formula is $N{{H}_{4}}OH$.
When the ammonium chloride is dissolved in water it splits into ions ($NH_{4}^{+}$ and $C{{l}^{-}}$). So the ammonium ion is a positive ion, the negative hydroxyl ion in the water gets attached to the ammonium ion forming ammonium hydroxide. The chloride ion is negative, so the positive hydrogen ions in the water get attached to the chloride ion forming hydrochloric acid. So the hydrochloric acid is a strong acid making the solution acidic because it will completely be dissociated into ions in the solution. So the solution will have more hydrogen ions. The reaction is given below:
$N{{H}_{4}}Cl+{{H}_{2}}O\to N{{H}_{4}}OH+HCl$

Note: The components of the salt decide whether the solution of the salt is acidic or basic. If the salt is made up of strong acid, then the solution of salt will be acidic and if the salt is made up of a strong base then the solution of the salt will be basic.