The question is incomplete, here is the complete question.
An aqueous solution at 25°C has a [tex]OH^-[/tex] concentration of [tex]1.9\times 10^{-8}M[/tex] . Calculate the [tex]H_3O^+[/tex] concentration. Be sure your answer has the correct number of significant digits.
Answer: The hydronium ion concentration of the solution is [tex]5.25\times 10^{-7}[/tex]
Explanation:
To calculate pOH of the solution, we use the equation:
[tex]pOH=-\log[OH^-][/tex]
We are given:
[tex][OH^-]=1.9\times 10^{-8}M[/tex]
Putting values in above equation, we get:
[tex]pOH=-\log(1.9\times 10^{-8})[/tex]
[tex]pOH=7.72[/tex]
To calculate the hydronium ion concentration, we first calculate pH of the solution, which is:
pH + pOH = 14
pH + 7.72 = 14
pH = 14 - 7.72 = 6.28
To calculate the hydronium ion concentration of the solution, we use the equation:
[tex]pH=-\log[H_3O^+][/tex]
We are given:
pH = 6.28
Putting values in above equation, we get:
[tex]6.28=-\log[H_3O^+][/tex]
[tex][H_3O^+]=5.25\times 10^{-7}[/tex]
Hence, the hydronium ion concentration of the solution is [tex]5.25\times 10^{-7}[/tex]