Which property of hydrogen fluoride causes it to be a weak acid in an aqueous solution?

1 Answer
anor277
Jul 1, 2016

#(i)# strength of the #H-F# bond, and #(ii)# charge density of the fluoride ion.

Explanation:

#H-X + H_2O rightleftharpoons H_3O^(+) + X^-#

The hydrogen fluoride bond is definitely stronger than the #H-Cl# or #H-Br# bond; and thus enthalpy disfavours the forward reaction. More importantly, the #F^-# ion is smaller and more polarizing than #Cl^-# or #Br^-#. #F^-# is thus disfavoured by entropy, in that it causes more solvent order.

Related questions
See all questions in Properties of Acids and Bases
Impact of this question
1255 views around the world
You can reuse this answer
Creative Commons License