Which of these compounds is a strong electrolyte?
O H2SO4
O C6H12O6 (glucose)
O CH3COOH (acetic acid)
The correct answer and explanation is:
The correct answer is H₂SO₄ (sulfuric acid).
Explanation:
Electrolytes are substances that dissociate into ions in water, allowing the solution to conduct electricity. Strong electrolytes dissociate completely, while weak electrolytes partially dissociate, and nonelectrolytes do not dissociate at all. Let’s analyze each compound:
1. H₂SO₄ (Sulfuric acid) – Strong Electrolyte
- Sulfuric acid is a strong acid and a strong electrolyte.
- It dissociates completely in water in two stages:
- H2SO4→H++HSO4−H_2SO_4 \to H^+ + HSO_4^- (complete dissociation)
- HSO4−⇋H++SO42−HSO_4^- \leftrightharpoons H^+ + SO_4^{2-} (partial dissociation for the second proton)
- The presence of free H+H^+, HSO4−HSO_4^-, and SO42−SO_4^{2-} ions makes the solution highly conductive.
2. C₆H₁₂O₆ (Glucose) – Nonelectrolyte
- Glucose is a molecular compound that does not ionize in water.
- It dissolves as intact molecules, not ions, so its solution does not conduct electricity.
- Glucose is a covalent compound and lacks ionic bonds, making it a nonelectrolyte.
3. CH₃COOH (Acetic acid) – Weak Electrolyte
- Acetic acid is a weak acid, which means it only partially dissociates in water: CH3COOH⇋CH3COO−+H+CH_3COOH \leftrightharpoons CH_3COO^- + H^+
- Since only a small fraction of the acetic acid molecules ionize, the solution has limited ion concentration and lower conductivity compared to a strong electrolyte.
Conclusion:
H₂SO₄ is the strong electrolyte among the given compounds because it dissociates completely and produces a high concentration of ions in water. In contrast, glucose does not ionize, and acetic acid only partially ionizes, making them a nonelectrolyte and a weak electrolyte, respectively. This complete dissociation makes H₂SO₄ ideal for electrical conductivity in aqueous solutions.