Consider the following statements for a gold sol:
$(I)$ It is a macromolecular colloid.
$(II)$ It is a lyophobic sol.
$(III)$ It is a negatively charged sol.
$(IV)$ It is a multimolecular colloid.
$(V)$ It is an associated colloid.
The correct statements are:

Which of the following is a lyophobic colloidal solution?

The coagulation of $100 \, mL$ of a colloidal sol of gold is completely prevented by the addition of $0.25 \, g$ of a substance '$X$' to it before adding $10 \, mL$ of $1 \% \ NaCl$ solution. The gold number of '$X$' is:

The charge of $SnO_2$-sol in alkaline and acidic medium are respectively (Hint: $SnO_2$ is amphoteric oxide).

Identify the option having the correct set of True $(T)$ or False $(F)$ statements with respect to colloidal solutions:
$(I)$ Lyophobic colloids are heavily solvated by the dispersion medium.
$(II)$ Multimolecular colloids are usually lyophilic.
$(III)$ Surface tension of a starch aqua sol will be lesser than that of water.
$(IV)$ Blood gets coagulated by the addition of $NaCl$.

Which of the following metal nanoparticles is used for coating the filter material that acts as an effective bacterial disinfectant?