Comment on the statement that “colloid is not a substance but a state of substance.”

Explanation

Classification of substances being crystalloids i.e., substances which form true solutions and colloids (i.e., substances which form colloidal sols) is not correct because the same substance can act both as crystalloid and colloid depending upon the nature of dispersion medium. For example NaCl when disolved in water is a crystalloid as it forms a true solution. On the other hand, NaCl when dispersed in benzene is a colloid because NaCl is not soluble in benzene. Colloid is simply a state in which the particle size of the dispersed phase is between 1-1000 nm.Thus colloid is not a substance, but it is a state of a substance which depends upon the particle size of the dispersed phase.