Write chemical equations to show what happens when an acid reacts with a
(i) metal
(ii) base and
(iii) carbonate
Write the name of the main product formed in each case.
Generated by claude-sonnet-4-6 · 2026-06-15 06:45 · grounding rag
Model Answer
(i) Acid + Metal → Salt + Hydrogen gas
$$\text{Zn} + \text{H}_2\text{SO}_4 \rightarrow \text{ZnSO}_4 + \text{H}_2\uparrow$$
Main product: Salt (zinc sulphate)
(ii) Acid + Base → Salt + Water (Neutralisation reaction)
$$\text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O}$$
Main product: Salt (sodium chloride)
(iii) Acid + Carbonate → Salt + Carbon dioxide + Water
$$\text{Na}_2\text{CO}_3 + 2\text{HCl} \rightarrow 2\text{NaCl} + \text{CO}_2\uparrow + \text{H}_2\text{O}$$
Main product: Salt (sodium chloride)
Source: Chapter 2, Acids, Bases and Salts
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Explanation
- Each sub-part carries 1 mark: ½ mark for the balanced equation + ½ mark for naming the main product is the typical examiner split.
- The common product in all three reactions is a salt — examiners expect you to state this explicitly.
- Use a standard example (Zn/H₂SO₄, NaOH/HCl, Na₂CO₃/HCl) — these are directly from the textbook and are safe choices.
- Ensure arrows for gas evolution (↑) are shown where relevant; it demonstrates awareness of physical states.