<Dl> <Dd> α A − = K a (H +) + K a (\ displaystyle \ alpha _ ((\ ce (A ^ -))) = (\ frac (K_ (a)) (((\ ce (H+))) + K_ (a)))) </Dd> </Dl> <Dd> α A − = K a (H +) + K a (\ displaystyle \ alpha _ ((\ ce (A ^ -))) = (\ frac (K_ (a)) (((\ ce (H+))) + K_ (a)))) </Dd> <Ul> <Li> φ = fraction of completion of the titration (φ <1 is before the equivalence point, φ = 1 is the equivalence point, and φ> 1 is after the equivalence point) </Li> <Li> C a, C b (\ displaystyle C_ (a), C_ (b)) = the concentrations of the acid and base respectively </Li> <Li> V a, V b (\ displaystyle V_ (a), V_ (b)) = the volumes of the acid and base respectively </Li> <Li> α A − (\ displaystyle \ alpha _ ((\ ce (A ^ -)))) = the fraction of the weak acid that is ionized </Li> <Li> K a (\ displaystyle K_ (a)) = the dissociation constant for the acid </Li> <Li> (H +), (OH −) (\ displaystyle (\ ce ((H+), (OH ^ -)))) = concentrations of the H and OH ions respectively </Li> </Ul> <Li> φ = fraction of completion of the titration (φ <1 is before the equivalence point, φ = 1 is the equivalence point, and φ> 1 is after the equivalence point) </Li>

Factors that determines the choice of an indicator for an acid-base titration