Question

$\mathrm{NaOH}+\mathrm{HCl}\to \mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}$; the above reaction is an example of ___ reaction.

Answer 1

Double displacement reaction: a chemical reaction in which two compounds in their aqueous state exchange their ions or radicals to form new substances is known as a double displacement reaction.

$\mathrm{AB}+\mathrm{CD}\to \mathrm{AC}+\mathrm{BD}$

Double displacement reactions are of two types:

Neutralization reaction: A chemical reaction in which acid and base react with each other to give salt and water. It is also known as an acid-base reaction.

$\underset{(\mathrm{potassium}\mathrm{hydroxide})}{\mathrm{KOH}\left(\mathrm{aq}\right)}+\underset{(\mathrm{sulphuric}\mathrm{acid})}{{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}\to \underset{(\mathrm{potassium}\mathrm{sulphate})}{{\mathrm{K}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}+\underset{\left(\mathrm{water}\right)}{{\mathrm{H}}_2\mathrm{O}}$

Precipitation reaction: A chemical reaction in which two compounds in their aqueous state react to form an insoluble solid (precipitate) as one of the products is known as a precipitation reaction.

For example:

$\underset{\mathrm{Ferric}\mathrm{chloride}}{{\mathrm{FeCl}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{hydroxide}}{3\mathrm{NaOH}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Ferric}\mathrm{hydroxide}}{\mathrm{Fe}{\left(\mathrm{OH}\right)}_3\left(\mathrm{aq}\right)\downarrow }+\underset{\mathrm{Sodium}\mathrm{chloride}}{3\mathrm{NaCl}\left(\mathrm{aq}\right)}$

In the below-given reaction acid (HCl) and base (NaOH) reacts with each other to give salt (NaCl) and water (H₂0).

$\underset{\mathrm{Sodium}\mathrm{hydroxide}}{\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydrochloric}\mathrm{acid}}{\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Sodium}\mathrm{chloride}}{\mathrm{NaCl}\left(\mathrm{aq}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

This is an example of an acid and base reaction which is also a neutralization reaction. It is also known as a double displacement reaction.

Hence, $\mathrm{NaOH}+\mathrm{HCl}\to \mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}$; the above reaction is an example of a neutralization reaction.