Answer
$pH = 13.30$
This is a basic solution.
Work Step by Step
1. Since $CsOH$ is a strong base:
$Initial[CsOH] = [OH^-] = 0.20M$:
2. Now, calculate the pH.
$pOH = -log[OH^-]$
$pOH = -log( 0.20)$
$pOH = 0.70$
$pH + pOH = 14$
$pH + 0.70 = 14$
$pH = 13.30$
3. At $25^{\circ}C$: $pH > 7$: basic solution.
