In a coagulation experiment , a sol of `As_2S_3` is mixed with distilled water and 0.2m solution of an electrolyte, AB so that total volume is 20 mL. It was found that all solutions containing more than 4.5mL of AB get coagulated within two minutes. What is the flocculation value of AB for `As_2S_3` ?

Explanation

Conc. of AB = 0.2 m
Volume of AB required to coagulate 20 mL solution =4.5mL
Amount of AB required to coagulated 20 mL solution `= (4.5 xx 0.2)/(1000) " moles " = (4.5 xx 0.2)/(1000) xx 1000` millimoles
= 0.9 millimoles
Millimoles of AB reqiured to coagulate 1 litre solution `= (0.9 xx 1000)/( 20 " for " As_2S_3) = 45`
`:. ` Flocculation value of AB =45