Question

An aqueous solution with a pH of 2.22 is diluted from 2.04 L to 3.92 L. What is the pH of the diluted solution?

Thanks in advance!

Answer 1

Answer – We are given, pH = 2.22 volume V1 = 2.04 L , V2 = 3.92 L

We need to calculate the pH of the diluted solution.

Method – First we need to calculate the concentration of proton from the given pH. By using dilution law we can calculate the new concentration proton. Then we can calculate the pH of the diluted solution.

We know formula for calculating the pH

pH = -log [H₃O⁺]

so,   [H₃O⁺] = 10^-pH

                    = 10^-2.22

                    = 0.00603 M

We know dilution law –

M1V1 = M2V2

0.00603 M * 2.04 L = M2 * 3.92 L

So, M2 = 0.00603 M * 2.04 L / 3.92 L

              = 0.00314 M

So, diluted solution [H₃O⁺] = 0.00314 M

Now pH for the diluted solution –

pH = -log [H₃O⁺]

     = - log 0.00314 M

      = 2.50

So, the pH of the diluted solution is 2.50