74. Solving a chemistry problem

9. The threshold of hydrosol coagulation under the action of potassium chloride is 9.25 mmol/l, and under the action of potassium sulfate 0.3 mmol/l. Using the Schulze-Hardy rule and the series following from the DLVO theory, determine the sign of the surface charge of the sol particles and calculate the coagulation thresholds caused by electrolytes: potassium chromate, sodium oxalate, magnesium chloride, magnesium sulfate, aluminum sulfate, potassium phosphate, potassium hexacyanoferriate.