Which of the following reactions does NOT represent a neutralisation reaction?

Correct option is D

The correct answer is option (d) Na$$_2$$​CO$$_3$$​ + HCl → NaCl + CO$$_2$$​ + H$$_2$$​O

Information booster :

Neutralisation Reaction

A neutralisation reaction occurs when an acid reacts with a base to form a salt and water.

Now, let's analyse each option:

 H₂SO₄ + Ca(OH)₂ → CaSO₄ + 2H₂O

• Sulfuric acid (H_2SO_4​) is an acid, and calcium hydroxide (Ca(OH)_2​) is a base.
• They react to form calcium sulfate (CaSO_4​) (a salt) and water (H_2O).
• This is a neutralisation reaction.

 CH₃COOH + NaOH → CH₃COONa + H₂O

• Acetic acid (CH₃COOH) is an acid, and sodium hydroxide (NaOH) is a base.
• They react to form sodium acetate (CH₃COONa) (a salt) and water (H₂OH).
• This is a neutralisation reaction.

 HCl + NaOH → NaCl + H₂O

• Hydrochloric acid (HCl) is an acid, and sodium hydroxide (NaOH) is a base.
• They react to form sodium chloride (NaCl) (a salt) and water (H₂O).
• This is a neutralisation reaction.

Na₂CO₃ + HCl → NaCl + CO₂ + H₂O

• Sodium carbonate (Na₂CO₃​) reacts with hydrochloric acid (HCl)to produce sodium chloride (NaCl) (a salt), carbon dioxide (CO₂​), and water (H₂O).
• Here, a gas (CO₂​) is produced, indicating that this is not a standard neutralisation reaction but rather a gas-evolution reaction.

The correct answer is option (d)

Na₂CO₃ + HCl → NaCl + CO₂ + H₂O is not a neutralisation reaction because it involves the evolution of carbon dioxide gas, which differentiates it from typical neutralisation reactions.