Help with chemistry please?

Question

Calculate [H3O+] for each of the following solutions and indicate whether the solution

is acidic or basic.

a. [OH-] = 5.1 X 10-4M b. [OH-] = 1.7 X 10-12 M c. [OH-] = 2.8 X 10-2M

Answer 1

-log [H+] = pH

-log [OH-] = pOH

do -log [OH-] for each one.. and you'll get the pOHs for each a, b, and c..

then subtract the pOH's from 14 to get the pH's

then if the pH is below 7 it's acidic and it's basic if it's greater than 7

Answer 2

since [H3O+] [OH-] = 1e-14

[H3O+]  = 1e-14 / [OH-]

Question

help with chemistry please?

Calculate [H3O+] for each of the following solutions and indicate whether the solution

is acidic or basic.

acicic has [H+] greater than 1.0 e-7

a. [OH-] = 5.1 X 10-4M  

[H3O+] = 2.0e-11  basic

b. [OH-] = 1.7 X 10-12 M

[H3O+] = 5.9e-3  acidic

c. [OH-] = 2.8 X 10-2M

[H3O+] = 3.6e-13  basic