Pka vs Ka

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DHavo_1E
Posts: 118
Joined: Sat Aug 17, 2019 12:17 am

Pka vs Ka

Postby DHavo_1E » Thu Nov 28, 2019 1:03 am

Hello!

Could someone explain what Pka and ka are conceptually and how they are different? Thank you!

Paige Lee 1A
Posts: 136
Joined: Sat Sep 07, 2019 12:16 am

Re: Pka vs Ka

Postby Paige Lee 1A » Thu Nov 28, 2019 2:17 pm

pKa represents various Ka values on a logarithmic scale, where pKa=-log[Ka] and p=-logbase 10

preyasikumar_2L
Posts: 101
Joined: Fri Aug 09, 2019 12:17 am

Re: Pka vs Ka

Postby preyasikumar_2L » Thu Nov 28, 2019 3:00 pm

Ka is the acid dissociation constant. pKa is the -log of this constant.

Michael Du 1E
Posts: 117
Joined: Sun Sep 22, 2019 12:16 am

Re: Pka vs Ka

Postby Michael Du 1E » Thu Nov 28, 2019 3:12 pm

Ka is given when there is a weak acid and is the acid dissociation constant. Since its a weak acid, the whole thing does not "fall" apart and we are given a dissociation constant as a result. Meanwhile, pKa is used to simply solve for the pH to determine its acidity on the ph scale.

Ziyan Wang 3J
Posts: 51
Joined: Wed Sep 18, 2019 12:22 am

Re: Pka vs Ka

Postby Ziyan Wang 3J » Sun Dec 01, 2019 10:04 am

pKa = -log[Ka], pKa usually have a range of 0 to 14

Sally Qiu 2E
Posts: 105
Joined: Fri Aug 30, 2019 12:18 am

Re: Pka vs Ka

Postby Sally Qiu 2E » Sun Dec 01, 2019 10:18 am

ka is the acid dissociation constant, and pka is the -log of Ka

Madeline Phan 1E
Posts: 103
Joined: Sat Aug 17, 2019 12:18 am

Re: Pka vs Ka

Postby Madeline Phan 1E » Sun Dec 01, 2019 10:33 am

pka is the negative log of Ka.

ASetlur_1G
Posts: 101
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Re: Pka vs Ka

Postby ASetlur_1G » Sun Dec 01, 2019 11:27 am

What is the pKa value actually describing?

Milisuryani Santoso 1L
Posts: 44
Joined: Thu Jul 11, 2019 12:15 am

Re: Pka vs Ka

Postby Milisuryani Santoso 1L » Sun Dec 01, 2019 7:33 pm

ASetlur_3I wrote:What is the pKa value actually describing?

pKa is just the pH of an acid.

Arvind 4G
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Re: Pka vs Ka

Postby Arvind 4G » Sun Dec 01, 2019 8:46 pm

pKa is a way to represent ka and is easier on the eyes as it uses the logarithmic scale.

Shail Avasthi 2C
Posts: 101
Joined: Fri Aug 30, 2019 12:17 am

Re: Pka vs Ka

Postby Shail Avasthi 2C » Mon Dec 02, 2019 10:34 am

For the following reaction:

HA ---> H+ + A-

Ka = [H+][A-]/[HA]
pKa = -log(Ka)

For stronger acids, Ka will be high and pKa will be low, and vice versa.


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