For the coagulation of a negative arsenic sulphide sol,what is the increasing order of the coagulating power of the ions $Na^{+}$,$Al^{3+}$,and $Ba^{2+}$?

The conditions given below are in the context of observing Tyndall effect in colloidal solutions:
$A$. The diameter of the colloidal particles is comparable to the wavelength of light used.
$B$. The diameter of the colloidal particles is much smaller than the wavelength of light used.
$C$. The diameter of the colloidal particles is much larger than the wavelength of light used.
$D$. The refractive indices of the dispersed phase and the dispersion medium are comparable.
$E$. The dispersed phase has a very different refractive index from the dispersion medium.
Choose the most appropriate conditions from the options given below:

Match the following types of colloidal systems given in List-$I$ with their respective names given in List-$II$.

List-$I$	List-$II$
$(A)$ Solid dispersed in liquid	$(I)$ Emulsion
$(B)$ Liquid dispersed in liquid	$(II)$ Foam
$(C)$ Gas dispersed in liquid	$(III)$ Gel
$(D)$ Liquid dispersed in solid	$(IV)$ Sol
-	$(V)$ Aerosol

Statement $I:$ For colloidal particles,the values of colligative properties are of small order as compared to values shown by true solutions at the same concentration.
Statement $II:$ For colloidal particles,the potential difference between the fixed layer and the diffused layer of opposite charges is called the electrokinetic potential or zeta potential.
In the light of the above statements,choose the correct answer from the options given below.

Identify the incorrect statement.

Pumice stone is an example of which type of colloidal system?