Which of the following phenomenon occurs when a chalk stick is dipped in ink?
Why is it important to have clean surface in surface studies?
It facilitates the adsorption of desired species. If surface is covered by the gases of air then it will not be available for adsorption of desired gases. So, it is very important to have clean surface in surface studies i.e., study of surface chemistry.
Why is chemisorption referred to as activated adsorption?
Chemisorption referred to as activated adsorption as it involves chemical bond formation between reactant and adsorbent molecules. Formation of chemical bond requires high activation energy. So, it is activated on increasing temperature.
What type of solutions are formed on dissolving different concentrations of soap in water?
At lower concentration, soap behaves as a normal solution of electrolyte in water. However, after a certain concentration, called critical micelle concentration, colloidal solution is formed due to aggregation of colloidal particles.
CMC for soap solution is $10^{-4}$ to $10^{-3} \mathrm{mol~L}^{-1}$.
What happens when gelatin is mixed with gold sol?
Gold sol is a solvent repelling sol i.e., a lyophobic sol and unstable in nature. Addition of gelatin stabilises the gold sol because gelatin forms lyophilic sol and act as a protective colloid.