The degree of ionisation (α) is the fraction of a weak acid or base that has ionised at equilibrium, equal to the amount ionised divided by the total amount initially present. It measures how completely a weak electrolyte dissociates. According to Ostwald's dilution law, the degree of ionisation increases as the solution is diluted.

电离度(α)是弱酸或弱碱在平衡时已电离的分数,等于电离的量除以最初存在的总量。它衡量弱电解质解离的完全程度。根据奥斯特瓦尔德稀释定律,电离度随溶液稀释而增大。