Science — AI-generated practice question

The reaction between sodium carbonate and dilute hydrochloric acid is:

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

Sodium carbonate reacts with dilute HCl to produce sodium chloride, water, and carbon dioxide gas. The CO₂ gas turns lime water milky.

Source: Chapter 2, Section 2.1.3

• The examiner expects the correctly balanced equation (1 mark) with correct formulae and coefficients — note the coefficient 2 before HCl and 2NaCl.
• The second mark is for state symbols (s, aq, l, g) and/or a brief statement of products. Many students lose marks by omitting CO₂ or forgetting to balance the equation. Remember: metal carbonates + acid → salt + water + CO₂.