4.2.3 Neutralisation of Acids and Salt Production

Reactions of Acids

1. Reactions with Pure Metals:

• Metals react with acids to produce salts and hydrogen gas. For example, sodium reacts with hydrochloric acid to form sodium chloride and hydrogen gas.

$$\ce{2Na (s) + 2HCl (aq) → 2NaCl (s) + H₂ (g)}$$

• The reactivity of the metal influences whether or not it will react with an acid. Highly reactive metals like sodium and magnesium react readily, while less reactive metals like copper and silver require stronger acids.

2. Reactions with Metal Oxides and Hydroxides:

• All metal oxides and hydroxides react with acids to form salts and water. This includes both soluble and insoluble bases.

$$Metal Oxide+Acid→Salt+Water$$ $$Metal Hydroxide+Acid→Salt+Water$$

• For instance, potassium hydroxide reacts with nitric acid to produce potassium nitrate and water.

$$\ce KOH(aq)+HNO3​(aq)→KNO3​(aq)+H2​O(l)$$

3. Reactions with Metal Carbonates:

• Metal carbonates react with acids to produce salts, water, and carbon dioxide.

$$Metal Carbonate+Acid→Salt+Water+Carbon Dioxide$$

Neutralisation Reactions

In all of these reactions, acids react with bases or metal compounds to produce salts. This is a type of neutralisation, where the acid and base cancel each other out, typically forming a neutral solution (pH 7) along with a salt.