Reactions of Bases

The reaction of bases with oxides of nonmetals involves the formation of salt and water. Non-metal oxides are acidic in nature, and when they react with bases, they neutralise each other, demonstrating the acidic property of non-metal oxides. This reaction highlights the role of nonmetal oxides as acid anhydrides.

For example:

SO₃ (g) + 2 NaOH (aq) → Na₂SO₄ (aq) + H₂O (l)

Reaction of Bases with Oxides of Non-Metals

1. Aim: To study the reaction of a base with oxides of nonmetals and observe the formation of salt and water.

2. Requirements: Sodium hydroxide solution (NaOH), carbon dioxide gas (CO₂), test tube, delivery tube, water, Bunsen burner or heat source, and non-metal oxides like sulphur trioxide (SO₃) or pre-prepared gas setup.

3. Procedure:

• Take a solution of sodium hydroxide (NaOH) in a test tube.
• Introduce carbon dioxide gas (CO₂) into the sodium hydroxide solution using a delivery tube.
• Observe the reaction in the test tube.
• Repeat the experiment with other non-metal oxides, such as SO₃, by bubbling them into a fresh solution of NaOH.
• Record any changes or formations in the test tube.

4. Observations: Effervescence is observed when the gas reacts with NaOH. The solution becomes clear as salt and water are formed. For example, when CO₂ reacts with NaOH, sodium carbonate (Na₂CO₃) and water are produced

CO₂ (g) + 2NaOH (aq) → Na₂CO₃ (aq) + H₂O (l)

5. Conclusion: Non-metal oxides, such as CO₂ and SO₃, react with bases like NaOH to form a salt and water, confirming their acidic nature. This reaction shows the neutralisation between an acidic oxide (nonmetal oxide) and a base.

Oxide of Non-Metal+ Base → Salt + Water

CO₂ (g) + 2 KOH (aq) → K₂CO₃ (aq) + H₂O (l)

SO₃ (g) + 2 NaOH (aq) → Na₂SO₄ (aq) + H₂O (l)