Colloidal solution of gold is in different colours like red,purple,blue and golden because of

Identify the sequential reactions involved in the Sol-Gel process.

Explain the terms with suitable examples:
$(i)$ Alcosol
$(ii)$ Aerosol
$(iii)$ Hydrosol.

Which one of the following is not a surfactant?

Match the following:

List-$I$ (Sol)	List-$II$ (Method of preparation)
$A$. $As_2S_3$	$IV$. Double decomposition
$B$. $Au$	$I$. Bredig's arc method
$C$. $S$	$II$. Oxidation
$D$. $Fe(OH)_3$	$III$. Hydrolysis

The correct answer is:

Consider the following statements related to colloids.
$(I)$ Lyophobic colloids are not formed by simple mixing of dispersed phase and dispersion medium.
$(II)$ For emulsions,both the dispersed phase and the dispersion medium are liquid.
$(III)$ Micelles are produced by dissolving a surfactant in any solvent at any temperature.
$(IV)$ Tyndall effect can be observed from a colloidal solution with dispersed phase having the same refractive index as that of the dispersion medium.
The option with the correct set of statements is