Question

Calculate the pH of a 0.155 M solution of KOH (to at least 2 decimal places)

Answer 1

`pH\text{ = 13.19}`

Step-by-step explanation:

Here, we want to calculate the pH of the given solution

Since the alkali is a strong one, dissociation is complete

That means the molarity of the solution equals the molarity of the hydroxide ions

Now, let us calculate the pOH

Mathematically:

`\begin{gathered} pOH\text{ = -log\lbrack OH}^-] \\ pOH\text{ = -log\lparen0.155\rparen} \\ pOH\text{ = 0.81} \end{gathered}`

Furthermore:

`\begin{gathered} pH\text{ + pOH = 14} \\ pH\text{ = 14-pOH} \\ pH\text{ = 14-0.81} \\ pH\text{ = 13.19} \end{gathered}`