Question

Which of the following represent a double displacement reaction?

• A. $2{\text{H}}_2\text{(g)}+{\text{O}}_2\text{(g)}\to$$2{\text{H}}_2\text{O(l)}$
• B. $2\text{Mg(s)}+{\text{O}}_2\text{(g)}$$\to 2\text{MgO(s)}$
• C. ${\text{AgNO}}_3\text{(aq)}+\text{NaCl(aq)}\to \text{AgCl}\text{(s)}+{\text{NaNO}}_3\text{(aq)}$
• D. $2{\text{H}}_2\text{(g)}+{\text{Cl}}_2\text{(g)}\to 2\text{HCl (g)}$

Answer 1

The correct option is C ${\text{AgNO}}_3\text{(aq)}+\text{NaCl(aq)}\to \text{AgCl}\text{(s)}+{\text{NaNO}}_3\text{(aq)}$

The reaction in which exchange of ions takes place between the compounds of the reactants is called a double displacement reaction.

The reaction between silver nitrate and sodium chloride involves exchange of their ionic counter parts to form the product. Hence, it is a double displacement reaction.

All the other three reactions given are combination reactions. Combination reaction is a reaction in which two or more elements or compounds combine to form a new product.