Answer:
1.380 × 10^-8 M
Step-by-step explanation:
The pH is the measure of alkalinity or acidity of a substance.
It is the negative logarithm of H+ ions concentration [H+].
pH = -log[H+]
pOH on the other hand is negative logarith of OH- concentration [OH-].
pOH = -log[OH-]
In this case;
pOH = 7.86
We can calculate the [OH-]
pOH = -log[OH-]
But, pOH = 7.86
pOH = -log[OH-]
-log[OH-] = 7.86
[OH-] = Antilog -7.86
= 1.380 × 10^-8 M
Therefore, [OH-] is 1.380 × 10^-8 M