For the coagulation of 500 mL of arsenious sulphide sol, 2mL of 1MNaCl is required. What is the flocculation value of NaCl.

2mL of 1MNaCl contains NaCl=21000=2mmol Thus 500mL of As2S3 sol require NaCl for complete coagulation = 2mmolHence 1L, i.e., 1000mL of the sol require NaCl for complete coagulation = 4 mmol Therefore, flocculation value of NaCl=4