Question

what is the pH of a 0.01M NaOH solution

Answer 1

Moles of NaOH = 0.01=10^-2
P(OH) = -log(H+)
=-log(10^-2)
=-2(log 10)
=-2. (Log 10=1)
pH=14 - P(OH)
=14-2
=12. (Answer)

Answer 2

The pH of a solution indicates the concentration of H+ ions in the solution. We know that NaOH is a base therefore it gives OH- ions.  

The relation between pH and pOH can be written as:

pH + pOH = 14  

pOH = - log [OH-]  

$\mathrm{NaOH} \rightarrow \mathrm{Na}^{+}+\mathrm{OH}^{-}$

Hence concentration of NaOH will be same as concentration of OH-.  

pOH = - log [ 0.01M]  

pOH = 2  

pH = 14 – pOH  =  14 -2  = 12