The balanced equation is option c) Zn + 2HCl → ZnCl₂ + H₂.
Balancing chemical equations is a crucial aspect of chemistry, ensuring that the number of atoms of each element is the same on both sides of the equation. Let's analyze each given chemical equation:
1. Mg₃N₂ + H₂O → 3MgO + 2NH₃:
- Left side: 3 Mg, 2 N, 2 H, 1 O
- Right side: 3 Mg, 2 N, 6 H, 1 O
- Unbalanced, as the number of H atoms is different on both sides.
2. C₃H₈ + 5O₂ → H₂O + 3CO₂:
- Left side: 3 C, 8 H, 10 O
- Right side: 1 C, 2 H, 3 O
- Unbalanced, as the number of C, H, and O atoms are not equal on both sides.
3. Zn + 2HCl → ZnCl₂ + H₂:
- Left side: 1 Zn, 2 H, 1 Cl
- Right side: 1 Zn, 2 H, 2 Cl
- Balanced, as the number of each type of atom is the same on both sides.
4. 3H₂SO₄ + 2Fe → Fe₂(SO₄)₃ + H₂:
- Left side: 6 H, 3 S, 8 O, 2 Fe
- Right side: 6 H, 3 S, 12 O, 2 Fe
- Unbalanced, as the number of O atoms and Fe atoms are different on both sides.
Therefore, The balanced equation is Zn + 2HCl → ZnCl₂ + H₂.
In summary, only the third equation is balanced. It satisfies the law of conservation of mass, ensuring that the same number of each type of atom exists on both sides of the chemical equation.