Question

Balance the following equations:
(i) \( \text{H}_2\text{SO}_4 (aq) + \text{NaOH} (aq) \rightarrow \text{Na}_2\text{SO}_4 (aq) + \text{H}_2\text{O} (l) \)
(ii) \( \text{MgCl}_2 (aq) + 2\text{AgNO}_3 (aq) \rightarrow \text{Mg(NO}_3)_2 (aq) + 2\text{AgCl} (g) \)

Hint:

When balancing chemical equations, always start with balancing atoms that appear only once on both sides, followed by elements that appear in multiple compounds.

Answer 1

(i) Balancing the first equation:
The given equation is: \[ \text{H}_2\text{SO}_4 (aq) + \text{NaOH} (aq) \rightarrow \text{Na}_2\text{SO}_4 (aq) + \text{H}_2\text{O} (l) \] - Balance the number of sodium (Na) atoms: There are 2 Na atoms in \( \text{Na}_2\text{SO}_4 \), so we need 2 NaOH on the left.
- Balance the hydrogen (H) atoms: There are 2 H atoms in \( \text{H}_2\text{SO}_4 \) and 2 NaOH, so hydrogen is balanced.
- The sulfur (S) and oxygen (O) atoms are already balanced.
Thus, the balanced equation is: \[ \text{H}_2\text{SO}_4 (aq) + 2\text{NaOH} (aq) \rightarrow \text{Na}_2\text{SO}_4 (aq) + 2\text{H}_2\text{O} (l) \]
(ii) Balancing the second equation:
The given equation is: \[ \text{MgCl}_2 (aq) + 2\text{AgNO}_3 (aq) \rightarrow \text{Mg(NO}_3)_2 (aq) + 2\text{AgCl} (g) \] - Balance the magnesium (Mg) atoms: One Mg atom on both sides.
- Balance the chlorine (Cl) atoms: 2 \( \text{Cl} \) atoms on both sides.
- Balance the silver (Ag) atoms: 2 \( \text{Ag} \) atoms on both sides.
- Balance the nitrate (NO₃) ions: 2 \( \text{NO}_3 \) ions on both sides.
Thus, the balanced equation is: \[ \text{MgCl}_2 (aq) + 2\text{AgNO}_3 (aq) \rightarrow \text{Mg(NO}_3)_2 (aq) + 2\text{AgCl} (g) \]
Conclusion:
The balanced equations are: 1. \( \text{H}_2\text{SO}_4 (aq) + 2\text{NaOH} (aq) \rightarrow \text{Na}_2\text{SO}_4 (aq) + 2\text{H}_2\text{O} (l) \)
2. \( \text{MgCl}_2 (aq) + 2\text{AgNO}_3 (aq) \rightarrow \text{Mg(NO}_3)_2 (aq) + 2\text{AgCl} (g) \)