Q1. [1] straightforward thorough-understanding
Which of the following best explains why an aqueous solution of sodium hydroxide conducts electricity?
(A) NaOH molecules carry charge through the solution as intact units.
(B) NaOH dissolves in water to produce Na⁺ and OH⁻ ions, which act as charge carriers.
(C) Water molecules break down into H⁺ and OH⁻ ions when NaOH is added, and it is these water-derived ions alone that conduct electricity.
(D) The high solubility of NaOH increases the density of the solution, enabling charge flow.
- A NaOH molecules carry charge through the solution directly.
- B NaOH dissolves in water to produce Na⁺ and OH⁻ ions, which carry the electric current.
- C NaOH reacts with water to produce H₂ gas, which aids conduction.
- D Water itself becomes a good conductor when NaOH is added due to the rise in temperature.
Generated by claude-sonnet-4-6 · 2026-06-26 01:04 · grounding rag
Model Answer
(B) NaOH dissolves in water to produce Na⁺ and OH⁻ ions, which carry the electric current.
Source: Acids, Bases and Salts (Chapter 2), Section 2.2.1
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Explanation
The textbook explicitly shows: NaOH(s) →(H₂O) Na⁺(aq) + OH⁻(aq). These free ions act as charge carriers, enabling conduction. Option A is wrong because intact molecules cannot carry charge. Option C is fabricated. Option D is incorrect — density has no role in ionic conduction. Examiners look for the key idea: ionic dissociation produces free ions → conduction.