Question

In a solution of potassium chloride when mixed with the silver nitrate solution, an insoluble white substance is formed. Write the chemical reaction involved and also mention the type of chemical 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.

AB+CD→AC+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.

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

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:

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

When a solution of potassium chloride is mixed with the silver nitrate solution then a white-colored precipitate (insoluble solid) of silver chloride is formed along with potassium nitrate. The following reaction takes place:

$\underset{\mathrm{potassium}\mathrm{chloride}}{\mathrm{KCl}\left(\mathrm{aq}\right)}+\underset{\mathrm{silver}\mathrm{nitrate}}{{\mathrm{AgNO}}_3\left(\mathrm{aq}\right)}\to \underset{\mathrm{potassium}\mathrm{nitrate}}{{\mathrm{KNO}}_3\left(\mathrm{aq}\right)}+\underset{\mathrm{silver}\mathrm{chloride}}{\mathrm{AgCl}}\downarrow$

This is an example of a precipitation reaction.