Science — AI-generated practice question

Metallic oxides are basic in nature because they react with acids to form salt and water.

Example: Copper oxide (a metallic oxide) reacts with dilute hydrochloric acid:

$$\text{CuO}(s) + 2\text{HCl}(aq) \rightarrow \text{CuCl}_2(aq) + \text{H}_2\text{O}(l)$$

This shows CuO is basic as it neutralises an acid.

Non-metallic oxides are acidic in nature because they react with bases to form salt and water.

Example: Carbon dioxide (a non-metallic oxide) reacts with sodium hydroxide:

$$\text{CO}_2(g) + 2\text{NaOH}(aq) \rightarrow \text{Na}_2\text{CO}_3(aq) + \text{H}_2\text{O}(l)$$

This shows CO₂ is acidic as it neutralises a base.

Source: Metals and Non-metals, Chapter 3; Acids, Bases and Salts, Chapter 2

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• The question is worth 3 marks: 1 mark for the metallic oxide statement + equation, 1 mark for the non-metallic oxide statement + equation, and 1 mark for correct balancing/reasoning.
• Always state why it is basic/acidic (reacts with acid/base respectively) — don't just write the equation.
• Equations must be balanced with correct state symbols for full marks.
• Common pitfall: students write the equation without explaining what it proves. Link the reaction back to the property.