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:

$100 \, cm^3$ of gold sol requires $10^{-4} \, g$ of gelatin to prevent coagulation when $1 \, cm^3$ of $10 \% \, NaCl$ solution is added. The gold number of gelatin is ............ .

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

Which of the following is not involved in coagulation?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Finest gold is red in colour,as the size of the particles increases,it appears purple then blue and finally gold.
Assertion $R$: The colour of the colloidal solution depends on the wavelength of light scattered by the dispersed particles.
In the light of the above statements,choose the most appropriate answer from the options given below:

Identify the correct statements from the following:
$I$) Sulphur sol is an example of a multimolecular colloid.
$II$) Starch sol is an example of an associated colloid.
$III$) Artificial rubber is an example of a macromolecular colloid.