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Difference in PH between strong and weak acids

Posted: Mon Jan 20, 2020 4:16 pm
by 405318478
could someone explain why, at the same concentration, a weak acid would have a higher PH than a strong acid?

Re: Difference in PH between strong and weak acids

Posted: Mon Jan 20, 2020 4:22 pm
by sarahsalama2E
remember that pH and H concentration are inverses, so something with a very high hydronium (h+) ion concentration, would be very acidic meaning that that its very low on the pH scale (lower is more acidic and basic is higher). So because of this logic, we know that a weak acid who has a low hydronium ion concentration is not as acidic and is more basic than a strong acid, therefore it has a higher pH.

Re: Difference in PH between strong and weak acids

Posted: Mon Jan 20, 2020 6:19 pm
by Joowon Seo 3A
A weak acid does not give up it's protons as easily as a strong acid. Therefore, there is a less concentration of hydronium ions and therefore a lower pH

Re: Difference in PH between strong and weak acids

Posted: Mon Jan 20, 2020 6:41 pm
by Hussain Chharawalla 1G
When adding a weak acid, how does the conjugate base affect pH?

Re: Difference in PH between strong and weak acids

Posted: Mon Jan 20, 2020 8:35 pm
by ayushibanerjee06
Remember that having a higher pH value means that it is not very acidic since it is closer to neutral pH = 7. Because of this, weaker acids have higher pHs because they are deprotonating less. Strong acids disassociate 100%, but since weak acids do not, their pH tends to be higher.

Re: Difference in PH between strong and weak acids

Posted: Tue Jan 21, 2020 10:43 am
by Katie Bart 1I
The stronger the acid, the lower the pH. The weaker the acid, the closer to 7 it is.

Re: Difference in PH between strong and weak acids

Posted: Tue Jan 21, 2020 11:18 am
by Kaylee Clarke 1G
The strong acids have a lower pH because they fully dissociate and have a lower hydronium concentration. Weak acids are the opposite.

Re: Difference in PH between strong and weak acids

Posted: Tue Jan 21, 2020 9:08 pm
by Luc Zelissen 1K
Kaylee Clarke 1G wrote:The strong acids have a lower pH because they fully dissociate and have a lower hydronium concentration. Weak acids are the opposite.

You are right that strong acids has a lower pH because they fully dissociate, but they have a higher hydronium concentration. The more H3O+ you have, the lower on the pH scale you go.

Re: Difference in PH between strong and weak acids

Posted: Tue Jan 21, 2020 11:31 pm
by 205291012
A strong acid has a smaller pH. A pH of 1 means it is stronger than a pH of 4. That's why a weak acid will have a higher pH than a strong acid.

Re: Difference in PH between strong and weak acids

Posted: Thu Jan 23, 2020 9:34 am
by Caroline Beecher 2H
Additionally, it is good to note that smaller pKa or pKb values mean that the acid or base is stronger, while smaller Ka or Kb values mean that the acid or base is weaker.

Re: Difference in PH between strong and weak acids

Posted: Thu Jan 23, 2020 9:34 am
by Caroline Beecher 2H
Additionally, it is good to note that smaller pKa or pKb values mean that the acid or base is stronger, while smaller Ka or Kb values mean that the acid or base is weaker.

Re: Difference in PH between strong and weak acids

Posted: Thu Jan 23, 2020 9:40 am
by LNgo 1G
Strong acids dissociate more than weak acids, resulting in a higher hydronium concentration in the solution. Where pH=-log[H3O+] a higher concentration of hydronium correlates to a lower pH value.