Question

Vinegar is a commercial form of acetic acid, HC2H3O2 (aq). One sample vinegar has a pH value of 2.4. State the pH value of a sample that has ten times fewer hydronium ions than an equal volume of a vinegar sample with a pH value of 2.4.

Answer 1

3.41 is  the pH value of a sample that has ten times fewer hydronium ions than an equal volume of a vinegar sample with a pH value of 2.4.

Explanation:

pH of the first sample of acetic acid = 2.4

to know the [H+] concentration in the acetic acid solution, the equation used is:

pH = -log [H+]

[H+] = $10^{-pH}$

[H+] = $10^{-2.4}$

[H+]  = 3.98 X $10^{-3}$ M

The concentration of H+ ion in first case is 3.98 X $10^{-3}$ M, the second sample has ten times less hydronium ion so concentration of first case is divided by 10.

3.98 x $10^{-4}$ M

Now pH of the sample having 10 times fewer ions of acetic acid:

pH = -log [H+]

putting the values in the above equation:

pH = -log [3.98 x $10^{-4}$ M]

pH = 3.41

If solution has ten times less hydronium ion the pH will change to 3.41.