pOH value is to measure how basic or acidic a solution is.
pOH is calculated using the following equation
pOH = -log [OH⁻]
since pOH is known, to calculate hydroxide ion concentration we need to find antilog
[OH⁻] = antilog (-4.65)
antilog can be calculated as follows
[OH⁻] = 10^(-4.65)
hydroxide ion concentration = 2.24 x 10⁻⁵ M