Question

What type of chemical reaction is ${\mathrm{NH}}_3+\mathrm{HCl}\to {\mathrm{NH}}_4\mathrm{Cl}$?

• A. Combination reaction
• B. Substitution reaction
• C. Decomposition reaction
• D. Double displacement reaction

Answer 1

The correct option is A

Combination reaction

Explanation for the correct option:

(A) Combination reaction

• “When two substances combine together to produce a single product, it is called a combination reaction.”
• In the given reaction, Ammonia (${\mathrm{NH}}_3$) and Hydrochloric acid ($\mathrm{HCl}$) react to form Ammonium chloride (${\mathrm{NH}}_4\mathrm{Cl}$). Therefore, it is a combination reaction.

${\mathrm{NH}}_3\left(\mathrm{aq}\right)+\mathrm{HCl}\left(\mathrm{aq}\right)\to {\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{aq}\right)$

Explanation for the incorrect options:

(B) Substitution reaction

• “When a group in a compound is replaced by another group, the reaction is called substitution reaction."
• No replacement of groups takes place in the given reaction. So, it is not a substitution reaction.

(C) Decomposition reaction

• “When a single reactant breaks down to produce simpler products, it is called decomposition reaction.”
• No breaking of the reactants occurs in the given reaction. Therefore, it is not a decomposition reaction.

(D) Double displacement reaction

• “When an exchange of ions takes place between the reactants, it is called double displacement reaction.”
• No exchange of ions occurs in the given reaction. Therefore, it is not a double displacement reaction.

Hence, option (A) is correct. The chemical reaction ${\mathrm{NH}}_3\left(\mathrm{aq}\right)+\mathrm{HCl}\left(\mathrm{aq}\right)\to {\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{aq}\right)$ is the Combination reaction.