Question

A salt is dissolved in water and the pH of this salt solution is measured with a universal indicator paper. If the pH of solution is less than 7, the salt is most likely to be ______.

Options

• CH₃COONa

• Na₂CO₃

• KCl

• NH₄Cl

Answer 1

A salt is dissolved in water and the pH of this salt solution is measured with a universal indicator paper. If the pH of solution is less than 7, the salt is most likely to be NH₄Cl.

Explanation:

A pH of less than 7 indicates the solution is acidic, characteristic of an acidic salt. Ammonium chloride (NH₄Cl) is formed from a strong acid (HCl) and a weak base (NH₄OH). In water, ammonium ions undergo cationic hydrolysis, releasing excess hydronium ions (H₃O⁺), thereby lowering the pH and turning the universal indicator paper yellow, orange, or red.