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:
(a) CH₃COONa
(b) Na₂CO₃
(c) KCl
(d) NH₄Cl

Answer 1

NH₄Cl
NH₄Cl is formed from a weak base, ammonium hydroxide (NH₄OH), and a strong acid, hydrochloric acid (HCl). On hydrolysis, NH₄Cl forms more H⁺ ions than OH^- ions. Thus, it is acidic, with a pH less than 7.