Question
When diluting a weak acid and a strong acid, why is it that the pH changes more significantly in the strong acid? (consider the equilibrium occurring)
With HCl
With HCl
Answers
DrBob222
With HCl, the acid is 100% ionized and for every factor of dilution (say 2x or 3x or 10x), the (H^+) is reduced by the same amount. That is if we dilute the HCl by 2, the (H^+) is just 1/2 of its original concn; if we dilute HCl by 10, the (H^+) is 1/10 the original concn.
However, in the case of a weak acid, for example CH3COOH (acetic acid), if we dilute the original by 2, more of the acetic acid ionizes
CH3COOH + H2O ==> CH3COO^- + H3O^+ which makes up for some of the dilution of the original H^+.
You can go through the calculations and show that this is so.
However, in the case of a weak acid, for example CH3COOH (acetic acid), if we dilute the original by 2, more of the acetic acid ionizes
CH3COOH + H2O ==> CH3COO^- + H3O^+ which makes up for some of the dilution of the original H^+.
You can go through the calculations and show that this is so.