Example of intrinsic colloid is

Arrange the following electrolytes in the increasing order of coagulation power for the coagulation of $As_2S_3$ sol.
$\mathop {K_2SO_4}\limits_{(I)}$ $\mathop {CaCl_2}\limits_{(II)}$ $\mathop {Na_3PO_4}\limits_{(III)}$ $\mathop {AlCl_3}\limits_{(IV)}$

The colour of a colloidal solution is due to

Which of the following is a correct statement?

Identify a nanomaterial having all three dimensions less than $100 \text{ nm}$?

The coagulation of $200 \ mL$ of a positive colloid took place when $0.73 \ g$ of $HCl$ was added to it. The flocculation value of $HCl$ for the colloid is