Answer:
[tex][OH^-]=2.455x10^{-3}M[/tex]
Explanation:
Hello there!
In this case, since a strong base produce OH ions in solution, it possible to first compute the pOH as shown below:
[tex]pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-11.39\\\\pOH=2.61[/tex]
Thus, via the definition of the pOH we can compute the concentration of the strong base as follows:
[tex]pOH=-log([OH^-])[/tex]
Thus, solving for the concentration we obtain:
[tex][OH^-]=10^{-pOH}=10^{-2.61}[/tex]
[tex][OH^-]=2.455x10^{-3}M[/tex]
Best regards!
