Ka/Kb question

[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?

[Chem_Mod]

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

[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?

[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-.

[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.