What is the pKa of HCl (aq)?

1 Answer
Jun 17, 2018

This is not measured in water....

Explanation:

..because in water, the protonolysis reaction is more or less quantitative...

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

This site gives #pK_a# values of #-8.08#, #-10.3#, and #-10.7# for #HCl#, #HBr#, and #HI# respectively. The order of acidity is what we would expect on the basis of hydrogen-halogen overlap. The other hydrogen halide, #HF#, is NOT a strong Bronsted acid for what reason?