Question

Use pH, pOH, [H3O+], and [OH–] relationships. (a) The hydroxide ion concentration in an aqueous solution of HCl is 3.4×10-13 M. Calculate [H3O+], pH, and pOH for this solution.

[H3O+] = 2.9x10^-4 M pH = 1.54 pOH = 12.46

(b) The pOH of an aqueous solution of HNO3 is 9.30. Calculate [H3O+], [OH-], and pH for this solution. [H3O+] = 2x10^-5 M [OH-] = 5x10^-10 M pH = 4.70

There is a error somewhere thank you for your help and can you give step by step aprreciate it