Question

Consider the following chemical equation I and II

1. \[\ce{Mg + 2HCl -> MgCl_2 +H_2}\]
2. \[\ce{NaOH +HCl -> NaCl + H_2O}\]

The correct statement about these equations is:

Options

• 'I' is a displacement reaction and 'II' is a  decomposition reaction.

• 'I' is a displacement reaction and 'II' is double displacement reaction.

• Both 'I' and 'II' are displacement reactions.

• Both 'I' and 'II' are double- displacement reactions.

Answer 1

'I' is a displacement reaction and 'II' is double displacement reaction.

Explanation:

\[\ce{Mg(s) + 2HCl(aq) ->MgCl_2(aq) + H_2(g)}\]

Magnesium displaces hydrogen in a chloride molecule in a single displacement reaction because it is more reactive than hydrogen. 

\[\ce{NaOH(aq) + HCl(aq) -> NaCl(aq) + H_2O(l)}\]

The reactants in a double displacement reaction exchange ions to create new molecules. The formation of salt (NaCl) and water (HOH) in the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) is an example of a double displacement reaction, more precisely a neutralisation reaction.