## pKa to Kb

Aliya Jain 2B
Posts: 101
Joined: Wed Sep 11, 2019 12:16 am

### pKa to Kb

im a little confused on how to convert pKa to Kb? I think theres multiple ways, but what's the easiest way to do it?

Nawal Dandachi 1G
Posts: 102
Joined: Sat Sep 28, 2019 12:16 am

### Re: pKa to Kb

pKa + pKb = 14, so solve for pKb. After finding pKb, use pKb = -log(kb) to find Kb

Brittney Hun 2C
Posts: 104
Joined: Wed Sep 11, 2019 12:15 am

### Re: pKa to Kb

Another way to do it is to turn the pKa into Ka first. Once you turn it into ka you can use the kw (water constant) to find the kb. Set the equation to be kb=kw/ka.

805373590
Posts: 101
Joined: Wed Sep 11, 2019 12:17 am

### Re: pKa to Kb

You can go from pka to ka by taking 10 to the power of negative pka and when you found ka you can easily divide 10 to the power of negative 14 by ka to get kb

Justin Seok 2A
Posts: 104
Joined: Sat Aug 24, 2019 12:15 am

### Re: pKa to Kb

So the simplest way would be to find Pkb using the equation 14=pka+pkb. Once you find your pkb, you can use it to find kb using 10^-pkb.

KaleenaJezycki_1I
Posts: 127
Joined: Sat Aug 17, 2019 12:18 am
Been upvoted: 2 times

### Re: pKa to Kb

What makes logical sense for me is to think, pka=-log(Ka), therefore Ka=10^-pka. Then we know Kw= Ka x Kb and so you should rearrange the equation so that Kw/Ka=Kb and now you have your Kb value! Make sure you take it slow and pay close attention.

AKhanna_3H
Posts: 104
Joined: Wed Sep 18, 2019 12:19 am

### Re: pKa to Kb

pKa + pKb = pKw. Therefore pKa + pKb = 14. 14 - pKb = pKa, and 14 - pKa = pKb.

Michelle Xie 2B
Posts: 99
Joined: Sat Aug 17, 2019 12:18 am

### Re: pKa to Kb

pKa + pKb is pKw, which is 14.

Kristina Rizo 2K
Posts: 105
Joined: Wed Sep 18, 2019 12:19 am

### Re: pKa to Kb

Nawal Dandachi 1G wrote:pKa + pKb = 14, so solve for pKb. After finding pKb, use pKb = -log(kb) to find Kb

I thought by doing the -log, you would get pKb? Wouldn't you need to 10^pKb to get Kb? Or did I switch it?

Leila_4G
Posts: 114
Joined: Sat Sep 14, 2019 12:17 am

### Re: pKa to Kb

Also, I'm forgetting the concentration equation for pKb, can someone help me with that? Thanks!

Posts: 103
Joined: Sat Aug 17, 2019 12:18 am

### Re: pKa to Kb

To find pka from pkb you can do 14-pka and vice versa.

Ian Morris 3C
Posts: 101
Joined: Wed Sep 18, 2019 12:18 am

### Re: pKa to Kb

14 minus the kPa will equal the pKb. Then Kb is equal 10 to the negative pKb.

Samuel Tzeng 1B
Posts: 103
Joined: Sat Aug 24, 2019 12:15 am

### Re: pKa to Kb

pKa + pKb = 14, then use pKb to solve for Kb