On addition of $1 \ mL$ solution of $10\% \ NaCl$ to $10 \ mL$ gold sol in presence of $0.025 \ g$ of starch,the coagulation is just prevented. The gold number of starch is

Which among the following is a zero-dimensional nanostructure?

For a positive sol, which of the following has the maximum coagulation power?

Butter is:

This equation represents the preparation of gold sol: $2 AuCl_3 + 3 HCHO + 3 H_2 O \rightarrow 2 Au + 3 HCOOH + 6 HCl$. What type of reaction is this?

Identify the correct statements from the following:
$(i)$ $A$ closed vessel containing $90 \%$ $CO_2$ and $10 \%$ $O_2$ is an aerosol.
$(ii)$ Milk is an emulsion.
$(iii)$ Smoke is an aerosol.
$(iv)$ Peptisation is a method of purification of colloidal solution.
$(v)$ Ultrafiltration is a method of purification of colloidal solution.