Question

What is the pH of a 0.0056 M HNO3 solution? Hint: HNO3 is a strong acid. Almost all of the acid will be ionized. Select one: A. 2.25 B. 11.11 C. 1.25 D. 0.056 E. 12.75

Answer 1

Answer: The pH is 2.25 (A)

Explanation: The reaction of HNO3 is;

HNO3(aq) ==> H+(aq) + NO3-(aq)

From the reaction, the concentration of H+ is equal to concentration of HNO3, that is

[H+] = [HNO3] = 0.0056=5.6×10^-3

pH= -log [H+]

pH= -log [5.6×10^-3]

pH= 3 - log 5.6

pH = 2.25

Therefore the pH of 0.0056HNO3 = 2.25