Calculate the pH of a 0.05 M solution of NaOH.

The pH is about 12.7.

Explanation:

NaOH is a strong base, meaning it will dissociate basically completely in solution to form  

N

a

+

and  

O

H

−

ions in solution.

One mole of  

O

H

−

ions is created for every mole of NaOH that is dissolved. If it's a .05 M solution of NaOH, then it can also be interpreted to be a .05M solution of  

O

H

−

.

p

O

H

(The pH scale for bases) can be found by taking the negative logarithm of  

O

H

−

concentration.

p

O

H

=  

−

log

[

.05

M

]

= 1.3.

However, we are trying to find  

p

H

, so we must use the formula

p

O

H

+

p

H

=

14

.

Now that we know  

p

O

H

=

1.3

,

p

H

=

14

−

1.3

=

12.7

.

(found the answer here https://socratic.org/questions/what-is-the-ph-of-a-0-050-m-naoh-solution)

b is the correct