Question

When ammonium chloride is added to ammonia solution, the pH of the resulting solution will be

• A. increased
• B. seven
• C. decreased
• D. unchanged

Answer 1

Answer: (C)

decreased

Answer 2

Due to common ion effect, rate of ionization of $NH _{4} OH$ decreases, so lower $\left[ OH ^{-}\right]$ is obtained.
Hence, pH value decrease.