Respuesta :
Step 1 - Understanding the definition of pOH
pOH is defined as:
[tex]pOH=-log[OH^-\rbrack[/tex]I.e., we can calculate the pOH by knowing the concentration of OH- in the solution.
Step 2 - Calculating the pOH of the given solutions
a) The first solution has a OH- concentration of 4.3 x 10-6 M. We just need to set this value in the definition of pOH:
[tex]\begin{gathered} pOH=-log4.3\times10^{-6}=-[log4.3+(-6)log10\rbrack \\ \\ pOH=-log4.3+6=6-0.63=5.37 \end{gathered}[/tex]b) The second solution has a OH- concentration of 2.0 x 10-6 M. Let's calculate its pOH:
[tex]\begin{gathered} pOH=-log2\times10^{-6}=-[log2+(-6)log10\rbrack \\ pOH=-log2+6=6-0.3=5.69 \end{gathered}[/tex]c) The third solution has a OH- concentration of 4.5 x 10-11 M. Let's calculate its pOH:
[tex]\begin{gathered} pOH=-log4.5\times10^{-11}=-[log4.5+(-11)log10\rbrack \\ pOH=-log4.5+11=11-0.65=10.35 \end{gathered}[/tex]Answer: the pOH of the solutions are, respectively, 5.37, 5.69 and 10.35
