Which of the following substances is a strong electrolyte?
The Correct Answer and Explanation is :
A strong electrolyte is a substance that completely dissociates into ions when dissolved in water. Examples include strong acids, strong bases, and most soluble salts.
Correct Answer:
Sodium chloride (NaCl) is a strong electrolyte.
Explanation:
- Definition of Electrolytes:
Electrolytes are substances that conduct electricity in an aqueous solution because they produce free-moving ions. They are classified as strong, weak, or non-electrolytes based on their ability to dissociate. - Strong Electrolytes:
A strong electrolyte fully dissociates into its constituent ions in water, meaning the solution contains only ions and no undissociated molecules. These include:
- Strong acids: HCl, HNO₃, H₂SO₄
- Strong bases: NaOH, KOH, Ba(OH)₂
- Soluble salts: NaCl, KBr, MgCl₂
- Why NaCl is a Strong Electrolyte:
- Ionic Nature: Sodium chloride is an ionic compound composed of Na⁺ (sodium) and Cl⁻ (chloride) ions.
- Complete Dissociation: When NaCl dissolves in water, it dissociates entirely into Na⁺ and Cl⁻ ions. No intact NaCl molecules remain in solution.
- Electrical Conductivity: The abundance of free ions allows the solution to conduct electricity effectively, making it a strong electrolyte.
- Contrast with Weak Electrolytes:
Weak electrolytes, like acetic acid (CH₃COOH), only partially dissociate in water. A significant proportion of molecules remain undissociated, resulting in fewer ions and lower conductivity. - Importance of Strong Electrolytes:
Strong electrolytes are crucial in biological systems (e.g., Na⁺ and K⁺ in nerve function) and industrial applications (e.g., electrolysis).
Understanding electrolyte strength helps in predicting conductivity and reaction mechanisms in solutions, which is essential in chemistry, biology, and engineering.