Question

What will be the resultant pH when 200ml of an aqueous solution of HCl (pH=2.0) is mixed with 300 ml of an aqueous solution of NaOH (pH=12.0) ?

Answer 1

Please check the attachment..

Hope its Help you!!

Answer 2

Answer:

pH = 11.301

Explanation:

Since, according to the question;

200 ml of an aqueous solution of HCl is mixed with 300 ml of an aqueous solution of NaOH.

The given pH of HCl is 2;

The given pH of NaOH is 12;

We have to find the resultant pH.

∵ [HCl] = $10^{-2} M$

∵ [NaOH] = $10^{-12} M$

So, the reaction goes like this :

$HCl + NaOH ⇒ NaCl + H_{2} O$

Since , before reaction;   $200 \times 10^{-2}$     $300 \times                      10^{-2}$

After reaction;

0              1                 2                    2

We will be finding the concentration of the hudroxide ion first.

∴ $[OH^{-} ]$ left from NaOH = $\frac{1}{500}  = 2 \times 10^{-3}$ M

∴$P_{OH} =  - log [OH^{-} ]$

  $P_{OH} =  - log [ 2 \times 10^{-3} ]$

The Ph of the hydroxide ion is calculated as $P_{OH} = 2.6989$

Since , we know that $P_{H} + P_{OH} = 14$

∴ The $P_{H}$ of the hydrogen ion is calculated as:

$P_{H} = 11.301$