pH and pOH are a measure of how acidic or how basic a
solution is and for most solutions, is measured on a scale of 0 to
14. The lower the number, the more acidic the solution is,
and the higher the number, the more basic the solution is.
Neutral solutions (not acidic or basic) have a pH of 7.
pH is measured on what we call a logarithmic scale,
that means that for every number the pH changes, the concentration of H^{+}
atoms changes by a factor of 10 (it becomes 10 times more acidic or
basic)
The graph above shows how the logarithmic pH scale
works.
The main things we need to know about pH and pOH are
14 = pH + pOH
pH = log[H]
pOH = log[OH]
Kw = 1x10^{14} = [H^{+}] * [OH^{}]
Complete the following table:
pH 
[H^{+}] 
[OH^{}] 
pOH 



4 


1x10^{2} 

pH = 14  pOH
so your first pH = 10
to get [H^{+}] from pH, take 10^{pH}
= 1x10^{10}
to get [OH^{}] from pOH, take 10^{pOH}
= 1x10^{4}
2nd line
find pOH by taking log(OH) = log(0.01) = 2
pH = 142 = 12
[H^{+}] = 10^{pH} = 1x10^{12}
So you end up with
pH 
[H^{+}] 
[OH^{}] 
pOH 
10 
1x10^{10} 
1x10^{4} 
4 
12 
1x10^{12} 
1x10^{2} 
2 