Question

As the [H+] in a solution decreases, what happens to the [OH–]?

Answer 1

As the concentration of [H+] decreases,
[OH-] increases.

Since [H+][OH-]=1E-14

Answer 2

Answer : When the concentration of $[H^{+}] decreases the concentration of [tex] [OH^{-}] increases and so does the pH value also increases.

Explanation : As the concentration of [tex] H^{+}$ decreases, the pH of the solution is observed to increase. The concentration of $OH^{-}$ increases with decrease of $H^{+}$ ions.

This can be related with this equation.

$[H^{+}]$ + $[OH^{-}]$ = $1X 10^{-14}$

as pH = - log $[H^{+}]$.

It is now, clearly understood that the decrease in concentration of $H^{+}$ will increase the concentration of $[OH^{-}]$ increases with increase in pH value and makes it more basic.