Question

Calculate the hydroxide ion concentration in an aqueous solution with a pH of 4.33 at 25°C. A) 2.1 * 10-10 M B) 9.7 * 10-10 M C) 4.7 x 10-5 M D) 3.8 x 10-5 M

Answer 1

Answer : The correct option is, (A) $2.1\times 10^{-10}M$

Explanation : Given,

pH = 4.33

pH : It is the negative logarithm of hydrogen ion concentration.

First we have to calculate the pOH.

$pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-4.33=9.67$

Now we have to calculate the $OH^-$ concentration.

$pOH=-\log [OH^-]$

$9.67=-\log [OH^-]$

$[OH^-]=2.1\times 10^{-10}M$

Therefore, the $OH^-$ concentration is, $2.1\times 10^{-10}M$