What is an acid according to Arrhenius?

1 Answer
Jun 7, 2017

According the Arrhenius, an acid is such a compound which in an aquous solution releases proton (or #H^+#).

Such compounds must fulfill two criteria -

1) First, it must be soluble in water (even if it is partly soluble, that'll do but, total insolubility of a compound disqualifies it to be regarded as an Arrhenius acid).

2) Second, it must be able to donate #H^+# in the solution.

Such acids may be classified as -

(a) Strong acids with a degree of dissociation #alpha = 1# which are almost completely dissociated.

Example - #H_2SO_4, HNO_3, HCl#

(b) Weak acids with a degree of dissociation #0 < alpha < 1# which are only partially dissociated but still donate #H^+# to some extent in aquous solution.

Example - #CH_3COOH, HCN, HCOOH#