Which of the following are correct statements

Options

A. Spontaneous adsorption of gases on solid surface is an exotherinic process as entropy decreases during adsorption.
B. Fomation of micelles takes place when temperature is below Kraft Temperature (T) and concentration is above critical micelle concentration (CMC).
C. A colloid of `Fe(OH)_3` is prepared by adding a little excess (required to completely precipitate `Fe^(+3)` ion s as `Fe(OH)_3` of NaOH in `FeCl_3` solution, then particles of this sol will move towards cathode during electrophoresis.
D. According to Hardy-Schulze rule the coagulating (flocculating) value of `Fe^(3+)` ions will be more than `Ba^(2+)` or `Na^+`.

Answer

A, C

Explanation

A) `Delta G = Delta H - T Delta S lt 0`
As `Delta S lt 0 so Delta H` has to negative for spontaneous adsorptin.
(B) Micelles formtion will take place above `T_k` and above CMC.
(C) This solution will be negatively charged.
(D) `Fe^(3+)` ions will have greater coagulation power so smaller coagulation value.