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pH of acids

Posted: Sun Mar 15, 2020 7:51 am
by ng1D
Why do solutions of weak acids have higher pH values than solutions of strong acids at the same concentration?

Re: pH of acids

Posted: Sun Mar 15, 2020 7:54 am
by Eesha Chattopadhyay 2K
Strong acids have a higher percent ionization than weak acids, so there is more H30 present in solutions with strong acids, causing them to have a lower pH.

Re: pH of acids

Posted: Sun Mar 15, 2020 7:56 am
by Gabriella Bates 2L
A strong acid has a tendancy to dissociate in water, and therefore will have a higher concentration of H+ ions and a lower pH. In contrast, a weak acid will not dissociate as much, and will therefore have a lower concentration of H+ ions and a higher pH.

Re: pH of acids

Posted: Sun Mar 15, 2020 1:07 pm
by Owen-Koetters-4I
Strong acids have higher percent ionization and as a result there is more h3o+ in solution, leading to a lower ph value

Re: pH of acids

Posted: Sun Mar 15, 2020 1:17 pm
by Jiyoon_Hwang_2I
Weak acids have higher pH because they’re essentially closer to 7 (neutral pH) and strong acids are on the farther side of the pH spectrum which is why they have a lower pH

Re: pH of acids

Posted: Sun Mar 15, 2020 2:11 pm
by Sydney Pell 2E
At the same concentration, weak acids will not dissociate as much as strong acids will. This means that weak acids have lower concentrations of H3O+ and therefore their pH will be closer to 7 while strong acids will have much lower pH because of their higher hydronium concentration.

Re: pH of acids

Posted: Sun Mar 15, 2020 3:02 pm
by Veronica Lu 2H
weak acids have a pH that's closer to 7 (neutral)

Re: pH of acids

Posted: Mon Mar 16, 2020 6:07 pm
by Ayushi2011
Strong acids dissociate completely, while weak acids don't which affects the ph.

Re: pH of acids

Posted: Mon Mar 16, 2020 6:17 pm
by Tauhid Islam- 1H
The stronger the acid, the lower the pH of the solution. You would expect weak acids to have higher pH values. Also pH is equal to -log concentration of H+ ions in the solutions. Because of partial disassociation of weak acids, you get less H+ ions meaning a higher pH in comparison to strong acids that completely disassociate.

Re: pH of acids

Posted: Mon Mar 16, 2020 7:20 pm
by Charlene Datu 2E
Weak acids are only partially ionized, in comparison to the strong acid that is completely ionized. With a lower concentration of [H+] in the solution, the weak acid would have a higher pH. Conversely, the strong acid would have a higher concentration of [H+] in the solution, resulting in a lower pH.

Re: pH of acids

Posted: Tue Mar 17, 2020 12:32 pm
by BAlvarado_1L
pH=-log[H+] and strong acids cause there to be a high [H+] than weak acids this strong acids have a pH closer to 0 while weak acids are closer to 7 on the scale of 0-7

Re: pH of acids

Posted: Tue Mar 17, 2020 8:38 pm
by SVajragiri_1C
Strong acids disassociate almost completely into hydronium ions, while weak acids only partially disassociate into hydronium ions. If the two acids are at the same concentration, the concentration of hydronium ions will be less for the weak acids. Since pH is the -log of the concentration of hydronium ions, the more hydronium ions there are, the lower the pH will be.

Re: pH of acids

Posted: Mon Jan 04, 2021 3:18 pm
by Madeline Ogden 3B
Since a higher pH signifies a more basic solution, weaker acids tend to have a higher pH than stronger ones. This is because pH refers to the content of hydronium (H30+) ions present in a solution. Weaker acids tend to not completely disassociate in water meaning that they'll have a higher content of H30+ ions and therefore a higher pH.

Re: pH of acids

Posted: Mon Jan 04, 2021 9:47 pm
by Karl Yost 1L
Recall: pH is the -log[H+].

The terms 'weak' and 'strong' are used to describe the extent that an acid/base dissociates in solution. Hydrochloric acid (HCl), for instance, is a strong acid, while ethanoic acid (CH3COOH) is a weak acid. Knowing this is important to answering your question, as a strong acid like HCl will completely dissociate in solution:

HCl (aq) --> Cl- (aq) + H+ (aq)

This means that, relative to a weak acid (which will only partially dissociate), the concentration of H+ will be greater.

Since pH the -log[H+], a greater concentration of hydrogen ions corresponds to a lower pH — and vice versa.