Question

The pH of a solution is 5.6. What are the hydrogen and hydroxide concentrations?

Answer 1

`pH =-log[H_3O^+]`

`[H_3O^+]*[OH^-]=10^-14`

Explanation:

The pH of a given solution is determined using the following formula:

`pH =-log[H_3O^+]`

To find the `[H_3O^+]` the formula must be manipulated as follows:

`log[H_3O^+]= -pH`

`[H_3O^+]=10^(-pH)`

Plugging the value of the pH in the equation gives:

`[H_3O^+]=10^-5.6`

`[H_3O^+]=10^0.4*10^(-6)`

`[H_3O^+]=2.51*10^-6 M`

In an aqueous solution,

`[H_3O^+]*[OH^-]=10^-14`

`[OH^-]=(10^-14)/([H_3O^+])`

`[OH^-]=(10^-14)/(2.51*10^-6) =3.98*10^-9 M`