Among the following methods:
$(i)$ Addition of an electrolyte
$(ii)$ Electrophoresis
$(iii)$ Addition of a protective colloid
$(iv)$ Addition of an oppositely charged sol
the coagulation of a lyophobic sol can be carried out by:

Which of the following ionic substances will be most effective in precipitating negatively charged sulphur sol? (All compounds are $100\%$ ionized)

Match the items in List-$I$ with the items in List-$II$.

List-$I$	List-$II$
$A$. Negatively charged sol	$I$. Emulsion
$B$. Milk	$II$. Kala-azar
$C$. Gold number	$III$. $FeCl_3$ solution is added to excess $NaOH$ solution
$D$. Colloidal antimony	$IV$. Protection of colloids

Choose the correct reason$(s)$ for the stability of the lyophobic colloidal particles.
$(A)$ Preferential adsorption of ions on their surface from the solution.
$(B)$ Preferential adsorption of solvent on their surface from the solution.
$(C)$ Attraction between different particles having opposite charges on their surface.
$(D)$ Potential difference between the fixed layer and the diffused layer of opposite charges around the colloidal particles.

$Fe(OH)_3$ sol and gold sol are positively and negatively charged,respectively. Which of the following statements is incorrect?

Which of the following ions will have the minimum coagulating value for the sol obtained by adding $FeCl_3$ solution to a slight excess of $NaOH$?