Question

the hydronium ion concentration of a 0.050 M solution of a weak acid is 5.9 X 10^-3 M. the acid-dissociation constant is 1.37 X 10^-4 at 25 celsius. what is the pH of this solution?
A. 0.077
B. 1.30
C. 2.23
D. 3.86
E. 5.13

Answer 1

You don't need most of the numbers.
pH = -log(H^+).