Verified answer

An oxyacid is an acid that contains oxygen. To be more specific, it is an acid that:

contains oxygen

contains at least one other element

has at least one hydrogen atom bound to oxygen

forms an ion by the loss of one or more protons.

The Ka expression is used with weak acids (that is the acid dissociates to a small extent in solution)

If you consider the oxyacid HNO3 , this dissociates almost completely in solution . If you try to calculate Ka for HNO3 you get:

Ka = [H+] [NO3-] / [NHO3]

Remember that [NHO3] is the molar concentration of the undissociated acid in solution . For HNO3 this is a very small number ( approaching 0) , therefore Ka becomes a large number

This is why Ka is not applied to strong acids,

But there is no problem in writing the Ka expression of a weak oxyacid such as HClO. The Ka expression is

Ka = [H+] [ClO-] / [HClO]

You see that the Ka is treated as any other weak acid when writing the Ka expression.

Ka expressions are usually reserved for weak acids. Some oxy acids such as HNO3 are essentially l00% ionized in dilute solutions so a Ka expression would not be needed to find pH or concentration of the unionized species.

But if you had a weak acid such as acetic, HC2H302 = H+ plus C2H302- which sets

the Ka expression would be Ka = (H+)(C2H302-) over (HC2H302)

( ) = moles per liter concentration

Absolutely, the same as regular acids