Which of the following can form a cationic micelle?

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?

On addition of $1 \ mL$ of $10 \%$ $NaCl$ to $10 \ mL$ gold sol in the presence of $0.038 \ g$ of starch the coagulation is just prevented. Then the value of gold number of starch is

Jelly is a colloidal solution of

The coagulation of $200 \ mL$ of a positive colloid took place when $0.73 \ g$ of $HCl$ was added to it without changing the volume much. The flocculation value of $HCl$ for the colloid is

The shape of colloidal particles is