## Ka and Kb as Inverses?

Nicole Elhosni 2I
Posts: 62
Joined: Fri Sep 28, 2018 12:28 am

### Ka and Kb as Inverses?

If we were given a reaction of a weak acid dissociating, then the reverse reaction would be the conjugate base. So if we are given Ka, can we find Kb by taking the inverse? Or should we use that Ka x Kb = Kw every time?

Arshiya
Posts: 69
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 1 time

### Re: Ka and Kb as Inverses?

Just to be safe, I would use what we know. And kA*kb=kw is given so use that.

JT Wechsler 2B
Posts: 62
Joined: Fri Sep 28, 2018 12:16 am

### Re: Ka and Kb as Inverses?

Since we know KaxKb = Kw that is what should be used to be safe.

lizettelopez1F
Posts: 29
Joined: Fri Sep 28, 2018 12:19 am

### Re: Ka and Kb as Inverses?

If we are not given Ka, can we just find Ka by using an ice table?

Kevin Tang 4L
Posts: 83
Joined: Fri Sep 28, 2018 12:28 am

### Re: Ka and Kb as Inverses?

lizettelopez1F wrote:If we are not given Ka, can we just find Ka by using an ice table?

I don't think it would be possible to find Ka value using an ice table if we don't know the variable x. We use the ice table so we can calculate the change in concentration knowing the Ka or Kb value. Instead, to find Ka value, you need to know the concentration of all the reactants and products (aqueous and gaseous) so you can set up an equilibrium equation or use the pKa or pKb value.

Hope this help and correct me if I'm wrong. Thanks!

Danny Zhang 4L
Posts: 62
Joined: Fri Sep 28, 2018 12:26 am

### Re: Ka and Kb as Inverses?

I don't believe I have ever seen Ka and Kb sharing an inverse relationship from the doing the textbook problems. I believe the only relevant relationship is Ka x Kb = Kw.

Helen Mejia 1I
Posts: 67
Joined: Fri Sep 28, 2018 12:24 am

### Re: Ka and Kb as Inverses?

Using the formula we were given Ka x Kb= Kw will be the best thing to do.

Jaqueline Monreal 2L
Posts: 57
Joined: Fri Sep 28, 2018 12:28 am

### Re: Ka and Kb as Inverses?

the safest thing to do is use the acid base formula to make sure

Return to “Equilibrium Constants & Calculating Concentrations”

### Who is online

Users browsing this forum: No registered users and 1 guest