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