The nature of charge on resulting colloidal particles when ${\mathrm{FeCl}}_3$ is added to excess of hot water is:

$3.12 \mathrm{g}$ of oxygen is adsorbed on $1.2 \mathrm{g}$ of platinum metal. The volume of oxygen adsorbed per gram of the adsorbent at $1 \mathrm{atm}$ and $300 \mathrm{K}$ in $\mathrm{L}$ is            

$\left[\mathrm{R}=0.0821 \mathrm{L} \mathrm{atm} {\mathrm{K}}^{-1} {\mathrm{mol}}^{-1}\right]$

Match List I with List II :
    List-I                                  List-II

Example of colloids            Classification
(a) Cheese                   (i) dispersion of liquid in liquid
(b) Pumice stone         (ii) dispersion of liquid in gas
(c) Hair cream             (iii) dispersion of gas in solid
(d) Cloud                     (iv) dispersion of liquid in solid

Choose the most appropriate answer from the options given below

In Freundlich adsorption isotherm, slope of $\mathrm{AB}$ line is: