Which substance increases the amount of hydroxide ions when dissolved in water?
Answer and explanation
Correct answer: Sodium hydroxide
According to the Arrhenius concept, a base increases the concentration of hydroxide ions in aqueous solution. Sodium hydroxide dissociates almost completely in water: NaOH(aq) → Na⁺(aq) + OH⁻(aq), so it is a strong base and clearly gives OH⁻ ions. Hydrochloric acid, lemon juice, and vinegar are acidic substances that increase hydrogen-ion concentration instead. Therefore, option C is correct.
Frequently asked questions
What is the correct answer to this question?
Sodium hydroxide
Why is this the correct answer?
According to the Arrhenius concept, a base increases the concentration of hydroxide ions in aqueous solution. Sodium hydroxide dissociates almost completely in water: NaOH(aq) → Na⁺(aq) + OH⁻(aq), so it is a strong base and clearly gives OH⁻ ions. Hydrochloric acid, lemon juice, and vinegar are acidic substances that increase hydrogen-ion concentration instead. Therefore, option C is correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
