Ka/Kb question

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

Ka/Kb question

Postby Evan Lee 2D » Tue Nov 29, 2016 2:38 pm

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?

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Re: Ka/Kb question

Postby Chem_Mod » Tue Nov 29, 2016 3:01 pm

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

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

Re: Ka/Kb question

Postby Caitlin Dillon 3G » Tue Nov 29, 2016 9:04 pm

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
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Joined: Fri Jul 01, 2016 3:00 am

Re: Ka/Kb question

Postby Anna Makridis_L1 » Wed Nov 30, 2016 7:53 am

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
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Re: Ka/Kb question

Postby Kevin Le 1L » Wed Nov 30, 2016 9:58 am

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.

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