Moles of HCl added to coagulate 200mL of colloid =
mass of HCl taken
molecular mass of HCl
=
0.73
(1+35.5)
=0.02mol =20mmol Now, we know Flocculation value is the minimum number of moles of electrolyte per litre required to coagulate a colloid. 200mL of sol required 20mmol of HCl So, 1000mL of sol required =
20
200
×1000 =100mmol Thus, the flocculation value of HCl for the colloid is 100 .