i need help with this question.

Question

What pH corresponds to each of the following: (a) (H-)=7.3*10^-5M, (b)(H+)=0.084M,(c)(OH-)= 3.3*10^-4M, (d) (OH-)= 0.042M?

Thank you.

Answer 1

a.
pH = -log(H^+)
pH = -log(7.3 x 10^-5)
pH = -(-4.14)
pH = 4.14

For questions involving OH, just find pOH from the (OH^-), then use pH + POH = 14