pH for weak acids

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Clarice Chui 2C
Posts: 81
Joined: Fri Aug 30, 2019 12:16 am

pH for weak acids

Postby Clarice Chui 2C » Fri Jan 17, 2020 5:29 pm

Why do solutions of weak acids have higher pH values than solutions of strong acids at the
same concentration?

VioletKo3F
Posts: 82
Joined: Sat Sep 07, 2019 12:18 am

Re: pH for weak acids

Postby VioletKo3F » Fri Jan 17, 2020 6:22 pm

Lower pH means a higher acidity and more H+ in the solutions. Stronger acids have a higher acidity and they also dissociate completely, meaning more H+.

Zaynab Hashm 2I
Posts: 94
Joined: Wed Sep 11, 2019 12:15 am
Been upvoted: 1 time

Re: pH for weak acids

Postby Zaynab Hashm 2I » Fri Jan 17, 2020 6:29 pm

pH is a measure of the concentration of H3O+ or H+, so it basically measures the concentration of hydronium ions in a solution.

strong acids dissociate/ionize way more compared to weak acids, and therefore release more H+.

since pH measures the concentration of H+ in the solution;
1. stronger acids will have more H+ and the pH will be lower according to the formula pH = -log[H3O+]
2. weaker acid will have less H+ and the pH will be higher according to the formula pH = -log[H3O+]

Tahlia Mullins
Posts: 85
Joined: Thu Jul 25, 2019 12:15 am

Re: pH for weak acids

Postby Tahlia Mullins » Fri Jan 17, 2020 8:26 pm

Since pH is determines by the concentration of H3O+ ions in the solution, the greater protonation yields a lower pH, and strong acids are known to be 100% dissociated, meaning a higher concentration of H3O+.

Alondra
Posts: 31
Joined: Tue Feb 26, 2019 12:15 am

Re: pH for weak acids

Postby Alondra » Mon Jan 20, 2020 1:29 am

I think of acids as having more protons and a lower value in the 0-14 range while bases have less protons and a higher value.
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SVajragiri_1C
Posts: 85
Joined: Thu Jul 11, 2019 12:16 am

Re: pH for weak acids

Postby SVajragiri_1C » Mon Jan 20, 2020 2:11 am

Weak acids disassociate into a less concentrated solution of hydronium ions in comparison to strong acids. Since pH is the negative log of hydronium ion concentration; weak acids would have higher pH values (negative log is basically the logarithm of 1/[hydronium ion])


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