What is [ OH - ] for a solution where pH = 4.80?

Question

PLEASE HELP!!!

Answer 1

To solve pH and pOH problems, use the ever-useful formula of pH + pOH = 14

Thus, pOH = 14 - 4.80 = 9.2

To get the actual concentration corresponding to the pOH,
pOH = - log [OH] or 9.2 = - log [OH]
- 9.2 = + log [OH]
then, take the antilogarithm to solve for just the term [OH]
or 10^-9.2 which is the same as 10 ^-10 x 10^.8

because -10 +.8 = - 9.2,

(Use calc to evaluate either 10^-9.2 or 10^.8)

Thus, [OH] = 6.31 x 10^-10 M ( note sig fig)

Answer 2

PH=14-POH
POH=-log[OH]=9.2
[OH]=6.31*10^-10 M