Question

The origin of charge on colloidal solution is:
This question has multiple correct options.
A.Frictional rubbing
B.Electron capture during Bredig’s arc method
C.Selective adsorption of ions on their surface
D.Due to addition of protective colloids

Answer 1

Charge on a colloid can be mainly formed by three ways. The concept of protective colloids is in reference to lyophilic and lyophobic colloids and has no relation with charge in colloids.

Complete step by step answer:
Let us look at the process happening in each of the above given option to find out whether they develop charge or not:
Frictional rubbing: In a colloidal solution both dispersed phase particles and dispersion medium particles are present. Due to rubbing with each other, there is a possibility of generation of some charge in a colloidal solution. Hence we will consider this option.
The colloidal particles prepared by Bredig’s arc method are charged colloids due to electron capture.
Selective adsorption of ions or preferential adsorption of ions means that the colloidal particles forms tend to adsorb the ions which are similar in their own lattice. For example, when silver nitrate is added to potassium iodide then colloidal solution of silver iodide forms, since iodide ions from potassium ions are in access. So they are absorbed by the silver iodide colloidal particles and hence colloidal particles get charged.

The correct options are A, B and C.

Note:
A colloidal solution is heterogeneous in nature, that is the solution is not uniform throughout. Though the solution is heterogeneous but the particles in the colloidal solution do not settle down. The most common example of colloids is the formation of curd from the coagulation of milk. The two phases develop in the solutions that are the dispersed phase and the dispersion phase.