Question

Which of the following is a neutralisation reaction?

• A. $\mathrm{NaOH}\left(\mathrm{l}\right)+\mathrm{HCl}\left(\mathrm{l}\right)\to \mathrm{NaCl}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$
• B. ${\mathrm{Na}}_2\mathrm{O}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2\mathrm{NaOH}\left(\mathrm{l}\right)$
• C. $2\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{MgO}\left(\mathrm{s}\right)$
• D. ${\mathrm{SO}}_3\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{l}\right)$

Answer 1

The correct option is A

$\mathrm{NaOH}\left(\mathrm{l}\right)+\mathrm{HCl}\left(\mathrm{l}\right)\to \mathrm{NaCl}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Explanation of correct option-

(A) $\mathbf{NaOH}\left(l\right)\mathbf{}\mathbf{+}\mathbf{}\mathbf{HCl}\left(l\right)\mathbf{}\mathbf{\to }\mathbf{}\mathbf{NaCl}\left(s\right)\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\left(l\right)$

Neutralization reaction - The reaction in which an acid reacts with a base to give salt and water.

For example - The reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH). It forms sodium chloride (NaCl) and water (H₂O)

• In this reaction the acid is neutralized by the base hence the reaction is called a neutralization reaction.
• When strong acid and a strong base react they give rise to a neutral salt.

Explanation of incorrect options-

(B) ${\mathbf{Na}}_{\mathbf{2}}\mathbf{O}\left(s\right)\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\left(l\right)\mathbf{}\mathbf{\to }\mathbf{2}\mathbf{NaOH}\left(l\right)$

The above-given reaction between sodium oxide (Na₂O) and water (H₂O) produces sodium hydroxide (NaOH) which is a base.

(C) $\mathbf{2}\mathbf{Mg}\left(s\right)\mathbf{}\mathbf{+}\mathbf{}{\mathbf{O}}_{\mathbf{2}}\left(g\right)\mathbf{}\mathbf{\to }\mathbf{2}\mathbf{MgO}\left(s\right)$

• The above-mentioned reaction is the formation of a metallic oxide by the oxidation process.
• When magnesium (Mg) reacts with oxygen (O₂), it forms magnesium oxide (MgO)

(D) ${\mathbf{SO}}_{\mathbf{3}}\left(g\right)\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\left(l\right)\mathbf{}\mathbf{\to }{\mathbf{H}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}\left(l\right)$

• This reaction is the formation of acid by dissolving a non-metallic oxide in water.
• When sulfur trioxide (SO₃) reacts with water, it forms sulfuric acid (H₂SO₄)

Hence, option (A) is correct.