Answer
Blue
Step-by-step explanation
To know what the color of the blue litmus paper will be, we need to dtermine the pH of the solution.
(OH⁻) = 5.0
Using pOH = -log (OH⁻)
pOH = -log (5.0)
pOH = -0.70
Note that pH + pOH = 14
put pOH = -0.70 into the formula to get pH
pH + (-0.70) = 14
pH - 0.70 = 14
pH = 14 +0.70 = 14.70
We can assume the pH of the solution falls in the alkaline/basic range.
Blue litmus paper turns red in acidic solution, while red litmus paper turns blue when the pH is alkaline.
You place a piece of blue litmus paper in the solution that has a hydroxide ion (OH⁻) concentration of 5.0, the color of the litmus paper will remain blue.