Degree of dissociation, α=Λ∞Λc where, Λc and Λ∞ are equivalent conductances at a given concentration and at infinite dilution respectively. ⇒α=4008.0=2×10−2 From Ostwald's dilution law (for weak monobasic acid) Ka or or =(1−α)Cα2Cα2=321(2×10−2)2=1.25×10−5