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Ka/Kb question

Posted: Tue Nov 29, 2016 2:38 pm
by Evan Lee 2D
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?

Re: Ka/Kb question

Posted: Tue Nov 29, 2016 3:01 pm
by Chem_Mod
Strong acids and bases do not have Ka or Kb values respectively.

Re: Ka/Kb question

Posted: Tue Nov 29, 2016 9:04 pm
by Caitlin Dillon 3G
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?

Re: Ka/Kb question

Posted: Wed Nov 30, 2016 7:53 am
by Anna Makridis_L1
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-.

Re: Ka/Kb question

Posted: Wed Nov 30, 2016 9:58 am
by Kevin Le 1L
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.