## Ka/Kb question

Acidity $K_{a}$
Basicity $K_{b}$
The Conjugate Seesaw $K_{a}\times K_{b}=K_{w}$

Evan Lee 2D
Posts: 18
Joined: Wed Sep 21, 2016 2:58 pm

### Ka/Kb question

Are Ka and Kb only used to determine the acidity and basicity of weak acids and bases, or can they be applied to strong acids/bases as well?

Chem_Mod
Posts: 19195
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 836 times

### Re: Ka/Kb question

Strong acids and bases do not have Ka or Kb values respectively.

Caitlin Dillon 3G
Posts: 26
Joined: Wed Sep 21, 2016 2:56 pm

### Re: Ka/Kb question

Can someone please explain why strong acids and strong bases do not have Ka and Kb values? Is it because they dissociate 100% into products?

Anna Makridis_L1
Posts: 13
Joined: Fri Jul 01, 2016 3:00 am

### Re: Ka/Kb question

Yes, they do not have kb or ka values because they are completely dissociated. Their concentration is assumed to be 100% ionized. For example if you have 0.1M of HCl, this means you would have 0.1M of H30+ ions and 0.1M of Cl-.

Kevin Le 1L
Posts: 17
Joined: Fri Jul 22, 2016 3:00 am

### Re: Ka/Kb question

Because strong acids and bases dissociate completely in water, you could use simple stoichiometry to determine the concentration of H3O+ or OH-. Because weak acids/bases don't dissociate completely in water, you're going to need to use the equilibrium constant.