Question

Give an example each of the following types of double displacement reaction:

When a gas is formed.

Answer 1

1. Double displacement reaction

A double displacement reaction is a chemical reaction in which the positive and negative ions of two compounds (reactants) change their positions to form new compounds (products).

2. Example of double displacement reaction

An example of such a reaction in which gas is formed is given as:

$$\begin{gathered} \mathrm{Mg}\left(\mathrm{s}\right)+2\mathrm{HCl}\left(\mathrm{aq}\right)\to {\mathrm{MgCl}}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right) \\ \mathrm{Magnesium}\mathrm{Hydrochloric}\mathrm{Magnesium}\mathrm{Hydrogen}\mathrm{gas} \\ \mathrm{acid}\mathrm{chloride} \end{gathered}$$

In this reaction, Magnesium and Hydrochloric acid react in such a way that Magnesium ion and Chloride ion combine together. The double displacement reaction occurs to form Magnesium chloride and Hydrogen gas as products. Here, Hydrogen gas is the gas formed in the double displacement reaction.