When they dissolve in water, what do all acids cause?

1 Answer
Mar 31, 2017

An increase in the concentration of the characteristic cation of the solvent, which is typically water.

Explanation:

Typically hydrogen halides dissolve in water according to the reaction:

#HX(g) + H_2O(l) rightleftharpoons H_3O^(+) + X^(-)#

For #HF# the equilibrium lies to the left. For the lower hydrogen halides, the equilibrium lies STRONGLY to the right, and causes an INCREASE in the concentration of #"hydronium ion"#, represented as #H_3O^+#, but more likely a transient cluster of 3-4 water molecules with an extra #H^+# attached, i.e. #H_9O_4^+# or #H_7O_3^+#.