If hydroxide ions are slowly added to an acidic solution, why will its pH increase?
Answer and explanation
Correct answer: Hydroxide ions combine with hydrogen ions to form water
An acidic solution contains a relatively high concentration of hydrogen or hydronium ions. Added hydroxide ions react with them in the neutralisation process: H⁺ + OH⁻ → H₂O. As H⁺ concentration falls, the negative logarithm used to define pH increases, so the solution becomes less acidic and its pH rises. The other options describe no valid consequence of adding hydroxide ions.
Frequently asked questions
What is the correct answer to this question?
Hydroxide ions combine with hydrogen ions to form water
Why is this the correct answer?
An acidic solution contains a relatively high concentration of hydrogen or hydronium ions. Added hydroxide ions react with them in the neutralisation process: H⁺ + OH⁻ → H₂O. As H⁺ concentration falls, the negative logarithm used to define pH increases, so the solution becomes less acidic and its pH rises. The other options describe no valid consequence of adding hydroxide ions.
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.
