The example of a heteropolar sol is

Which of the following pairs is correctly matched?

Given below are two statements ($S-I$ and $S-II$):
$S-I$: Scattering of light by dispersed particles of a colloidal system is known as the Tyndall effect.
$S-II$: The diameter of the dispersed particles should not be much smaller than the wavelength of the light used.
Choose the most appropriate answer from the options given below.

In each of four separate beakers $(I, II, III, IV)$,$X \ mL$ of $y \ M \ Fe_2O_3 \cdot xH_2O$ colloidal solution is present. Equal volume and equal concentration of $KCl, K_4[Fe(CN)_6], K_3PO_4$ and $K_2SO_4$ were added into $I, II, III$ and $IV$ respectively. The efficiency of precipitation in these beakers follows the order:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Dissolved substances can be removed from a colloidal solution by diffusion through a parchment paper.
Reason $(R)$: Particles in a true solution cannot pass through parchment paper but the colloidal particles can pass through the parchment paper.
In the light of the above statements,choose the correct answer from the options given below.

On addition of $1 \, mL$ solution of $10\% \, NaCl$ to $10 \, mL$ gold sol in the presence of $0.25 \, g$ of starch,the coagulation is just prevented. What is the gold number of starch?