Percent Protonation/Deprotonation

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Ananya Ravikumar 1I
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Joined: Mon Jan 09, 2023 8:28 am

Percent Protonation/Deprotonation

Postby Ananya Ravikumar 1I » Thu Feb 02, 2023 1:07 am

Is the percent protonation of a base the {(concentration of conjugate acid at equilibrium)/(initial concentration of base)}*100 or the {[OH-] at equilibrium)/(initial concentration of base)}*100?
Similarly, does the percent deprotonation for an acid relate to the equilibrium concentration of its conjugate base or H3O+?

Just making sure since the products of a dissociation reaction may not always be present in the same number of moles
Thanks!

Shania Hao 3L
Posts: 39
Joined: Mon Jan 09, 2023 10:17 am

Re: Percent Protonation/Deprotonation

Postby Shania Hao 3L » Thu Feb 02, 2023 7:03 am

That is a good question, I would also like clarification on this.
In the example given in the textbook for the percent protonation of a base, the concentration of the conjugate acid was used. For the example of the percent deprotonation of a weak acid, the [H3O+] was used. Thus, I believe to calculate the percent protonation/deprotonation, you are considering the part that had [H+] added to it, meaning it would be the [BH+] in a base and [H3O+] in an acid.

Ananya Ravikumar 1I
Posts: 41
Joined: Mon Jan 09, 2023 8:28 am

Re: Percent Protonation/Deprotonation

Postby Ananya Ravikumar 1I » Thu Feb 02, 2023 11:38 am

Thank you!
Last edited by Ananya Ravikumar 1I on Wed Feb 08, 2023 1:32 pm, edited 1 time in total.

Payton Zarceno 1E
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Joined: Mon Jan 09, 2023 2:37 am

Re: Percent Protonation/Deprotonation

Postby Payton Zarceno 1E » Sun Feb 05, 2023 8:12 pm

Hi! I think Shania is correct, when you're considering a base I believe you need to use [BH+]/[the initial B + new concentration of B].

Emmy Flores 3F
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Re: Percent Protonation/Deprotonation

Postby Emmy Flores 3F » Sun Feb 05, 2023 9:53 pm

Yes, think how percent protonation is the how much a molecule gains a proton while deprotonation is the percent of the molecule that gives away protons.

Anna_Aldridge_2C
Posts: 35
Joined: Mon Jan 09, 2023 9:28 am

Re: Percent Protonation/Deprotonation

Postby Anna_Aldridge_2C » Sun Feb 05, 2023 11:58 pm

Hi!
I believe the percent protonation in your first assumption is correct. The protonation will take a proton (H+) from the water and bond with the base, making HB+ and OH-. Because the focus is on the ratio between the initial amount of base and the amount that is protonated, the calculation would be [HB+]/[Binitial]. Similarly, the percent deprotonation is the ratio between the conjugate base (amount that has had protons removed) and the initial amount of acid, and not to equilibrium.


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