Question

Which of the following is a displacement reaction?

• A. $\text{CaO(s)}+{\text{H}}_2\text{O(l)}\to {\text{Ca(OH)}}_2\text{(aq)}$
• B. ${\text{MgCO}}_3\text{(s)}\to \text{MgO(s)}+{\text{CO}}_2\text{(g)}$
• C. $2\text{Na}\text{(s)}+2{\text{H}}_2\text{O(l)}\to 2\text{NaOH(aq)}+{\text{H}}_2\text{(g)}$
• D. ${\text{H}}_2\text{(g)}+{\text{Cl}}_2\text{(g)}\to 2\text{HCl}\text{(g)}$

Answer 1

The correct option is C $2\text{Na}\text{(s)}+2{\text{H}}_2\text{O(l)}\to 2\text{NaOH(aq)}+{\text{H}}_2\text{(g)}$

The chemical reaction in which a more reactive element displaces a less reactive element from its compound is called displacement reaction.

Among the given options, the reaction between sodium and water to form sodium hydroxide and hydrogen gas is an example of a displacement reaction. This is because sodium, which is more reactive than hydrogen, displaces it from water.