The coagulation values in millimoles per litre of the electrolytes used for the coagulation of As₂S₃ are given below:
I. (NaCl) = 52
II. (BaCl₂) = 0.69
III. (MgSO₄) = 0.22
The correct order of their coagulating power is :

Coagulation power α 1/coagulation value
The coagulation value is the minimum concentration of an electrolyte required to cause coagulation of a sol.
Lower the coagulation value, higher is the coagulation power.
The coagulation values are given as:
NaCl = 52 mmol/L
BaCl₂ = 0.69 mmol/L
MgSO₄ = 0.22 mmol/L
Therefore, the order of coagulation power is:
MgSO₄ > BaCl₂ > NaCl
III > II > I