Question

A solution has a pOH of 7.1 at 10∘C. What is the pH of the solution given that Kw=2.93×10−15 at this temperature? Remember to report your answer with the correct number of significant figures

Answer 1

Answer : The pH of the solution is, 7.4

Explanation : Given,

pOH = 7.1

$K_w=2.93\times 10^{-15}$

First we have to calculate the value of $pK_w$.

The expression used for the calculation of $pK_w$ is,

$pK_w=-\log [K_w]$

Now put the value of $K_w$ in this expression, we get:

$pK_w=-\log (2.93\times 1-^{-15})$

$pK_w=15-\log (2.93)$

$pK_w=14.5$

Now we have to calculate the pH of the solution.

As we know that,

$pH+pOH=pK_w$

Now put all the given values in this formula, we get:

$pH+7.1=14.5$

$pH=7.4$

Therefore, the pH of the solution is, 7.4