Answer: The concentration of hydroxide ions is 3.5 x 10^-11 M.
Explanation:
HBr is a strong acid, thus the concentration of HBr wil be the same of H+ ions. Then, we have to calculate the H+ concentration:
[tex][H^{+}]=\frac{mol H^{+}}{L of solution} = \frac{4.00*10^{-3} mol }{14.0 L} =0.000286 M [H^{+}][/tex]
Now, we can calculate the pH of the solution:
[tex]pH=-log[H^{+}]=-log [0.000286]=3.54[/tex]
With the pH, now we can obtain the pOH value:
[tex]pOH= 14 - pH = 14 - 3.54 = 10.46[/tex]
Finally, we can calculate the OH- concentration with the pOH formula:
[tex]pOH=-log[OH^{-}][/tex]
[tex][OH^{-}]=10^{-pOH} = 10^{-10.46} = 0.000000000035 M [OH^{-}]= 3.5*10^{-11} M [OH^{-}][/tex]
Therefore, the concentration of hydroxide ions is 3.5 x 10^-11 M.
