According to Graham,colloids are those substances which are

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:

When an excess of a very dilute aqueous solution of $KI$ is added to a very dilute aqueous solution of silver nitrate,the colloidal particles of silver iodide are associated with the Helmholtz double layer in the form of:

Given below are two statements:
Statement $I:$ In the coagulation of a negative sol,the flocculating power of the three given ions is in the order - $Al^{3+} > Ba^{2+} > Na^{+}$
Statement $II:$ In the coagulation of a positive sol,the flocculating power of the three given salts is in the order - $NaCl > Na_{2}SO_{4} > Na_{3}PO_{4}$
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following contributes to the extra stability of lyophilic colloids?

An emulsifier: