When the dispersion medium is water,the colloidal system is called:

Milk is an example of a/an ...... .

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

Various types of colloids are given below. Match Column $X$ with Column $Y$.

$X$ (Colloid)	$Y$ (Classification)
$I$. Smoke	$A$. Sol
$II$. Gelatin	$B$. Aerosol
$III$. Soap lather	$C$. Emulsion
$IV$. Milk	$D$. Foam

An example of a water-in-oil $(W/O)$ type emulsion is ......

Explain what is observed:
$(i)$ When a beam of light is passed through a colloidal sol.
$(ii)$ An electrolyte,$NaCl$,is added to hydrated ferric oxide sol.
$(iii)$ Electric current is passed through a colloidal sol.