Question

50 ml of 0.2 M ammonia solution is treated with 25 ml of 0.2 M hcl if pKb of ammonia solution is 4.75, the pH of the mixture will be

Answer 1

Hi, consider the answer below;

50 ml of 0.2 M ammonia solution is treated with 25 ml of 0.2 M hcl if pKb of ammonia solution is 4.75, the pH of the mixture will calculated as follows.

First calculate the number of moles in each case;

moles of ammonia solution= 50 x 0.2/1000= 0.01 moles

moles of Hydrochloric acid is = 25 x 0.2/1000= 0.005 moles

Therefore number of moles in the reaction = 0.01 - 0.005=0.005 moles

concentration = 0.005/75 = 6.67 x 10^-5 M

pH = -log (6.67 x 10^-5)

pH= 4.2