What is the effect of temperature and concentration on acid disociation constant?

1 Answer
anor277
Jun 4, 2018

Well, equilibrium constants are generally INDEPENDENT of concentration...

Explanation:

...however, we would expect that for weak acids, #HX#, whose protonolysis reaction we would represent as the equilibrium ...

#HX(aq)+H_2O(l)rightleftharpoonsH_3O^+ + X^-#

Now this is a BOND-BREAKING reaction...i.e. we break the #H-X# bond....and we expect that if we supply heat, we should drive the equilibrium to the right. And so let us look at some data..

#2H_2O(l) rightleftharpoonsH_3O^+ + HO^-# #K_a=10^-14# at #298*K#...

According to this site #pK_a=6.63# at #50# #""^@C#, and #pK_a=6.14# at #100# #""^@C#. Perhaps you could work out values for #K_a# at each temperature. Are these data in accord with our prediction? Why or why not?

Related questions
See all questions in Stoichiometry with Acid and Base Dissociation
Impact of this question
2448 views around the world
You can reuse this answer
Creative Commons License