Indicators of strong or weak acid/base

[Jessie_Chen_2L]

Hi, I am still sort of confused as to how we can tell if an acid or a base is strong or weak and why most inorganic acids are strong compared to organic acids. I know that strong acids lose a proton easily and the resulting anion must be stable, but I remember that we can somehow tell from K_a and K_b.

Thanks!

[Alexander Chen 3N]

A simple indicator is if the question gives you the Ka or Kb, you should assume that it is a weak acid/base. This is because a strong acid/base has a very large Ka/Kb, so we just say that the reaction goes to completion and the acid is fully dissociated (HCl fully becomes H+ and Cl-).

[204751840 2E]

Just to clarify, this means that strong acids and bases have no Ka or Kb?

[Kathy Vu 3L]

Strong acids do have a Ka value, they are just very large since strong acids dissociate almost completely, therefore the products/reactants ratio would be very high, making the Ka value high.