Consider a general reaction where a ligand L and a metal ion Mn+ form a complex with m number of ligands (L) coordinated to each metal ions. Assume the metal is colorless. The ligand and metal solutions were mixed at molar fractions (and same total molar concentration). The absorbances of the mixtures were recorded at 500nm which is the lamda max of the metal ligand complex and the ligand is transparent at 500nm

Question

Consider a general reaction where a ligand L and a metal ion Mn+ form a complex with m number of ligands  (L) coordinated to each metal ions. Assume the metal is colorless. The ligand and metal solutions were mixed at molar fractions (and same total molar concentration). The absorbances of the mixtures were recorded at 500nm which is the lamda max of the metal ligand complex and the ligand is transparent at 500nm
a) What approximately experimental conditions would you suggest to make this experiment a sucess
b) Write a balanced reaction between Mn ion and L (show all work)
c) Suggest a plausible structure to the product of the reaction
d) Sketch the spectrometric titration plot if 25mL sample of Mn+ (0.1M) were titrated vs a solution of the lignad L (0.25M) and the reaction solution was monitored at 500m.

L is pyrocatechol violet which pK1= 7.8, pK2= 9.8, pK3=11.7

For b) I think the answer is M +L -> ML but not sure. Any help is greatly appreciated