a solution of oh negative ions is added to a beaker of pure water 25 degrees celcius to a final concentration of 137 nM calculate the ph of the solution
Are you new to chemistry. Two things to keep in mind.
1. Start sentences with a capital letter and put in periods. Otherwise it makes it difficult to know the question.
2. Find the caps key and use it. Co, CO, and co means something different.
3. Note correct spelling of Celsius.
137 mM I suppose means 137 millimolar. That is 0.137 M.
pOH = -log(OH^-) = -log 0.137
pOH = -(=0.863) = 0.863
pH + pOH = pKw = 14.
You know pOH and pKw, solve for pH.