A colloidal solution of ferric oxide is prepared by two different methods as shown below. a. What is the charge on colloindal particles in the two test tubes `(A)` and `(B)`? b. Give reasons for the origin of charge.

A colloidal solution of ferric oxide is prepared by two different meth

1.	A colloidal solution of ferric oxide is prepared by two different methods as shown below. a. What is the charge on colloindal particles in the two test tubes `(A)` and `(B)`? b. Give reasons for the origin of charge.
Answer» Colloidal particles of test tube (A) are positively charged where as colloidal particles of test tube (B) are negatively charged. In test tube (A). `Fe^(3+)` is adsorbed on the precipitate `Fe_(2)O_(3).xH_(2)O` [or `Fe_(2)O_(3).xH_(2)O//Fe^(3+)` is formed]. In test tube (B). `overset(ɵ)(OH)` ions is adsorbed on the precipitate `Fe_(2)O_(3).xH_(2)O` [or `Fe_(2)O_(3).xH_(2)O//overset(ɵ)(OH)` is formed].Colloidal particles of test tube (A) are positively charged where as colloidal particles of test tube (B) are negatively charged. In test tube (A). `Fe^(3+)` is adsorbed on the precipitate `Fe_(2)O_(3).xH_(2)O` [or `Fe_(2)O_(3).xH_(2)O//Fe^(3+)` is formed]. In test tube (B). `overset(ɵ)(OH)` ions is adsorbed on the precipitate `Fe_(2)O_(3).xH_(2)O` [or `Fe_(2)O_(3).xH_(2)O//overset(ɵ)(OH)` is formed].