Identify the negatively charged sol from the following.

Which one of the following is most effective in causing the coagulation of an $As_2S_3$ sol?

Assertion : $Fe^{3+}$ can be used for coagulation of $As_2S_3$ sol.
Reason : $Fe^{3+}$ reacts with $As_2S_3$ to give $Fe_2S_3$.

What happens when gelatin is mixed with a gold sol?

The correct statement$(s)$ related to colloids is(are):
$(A)$ The process of precipitating colloidal sol by an electrolyte is called peptization.
$(B)$ Colloidal solution freezes at a higher temperature than the true solution at the same concentration.
$(C)$ Surfactants form micelles above the critical micelle concentration $(CMC)$. $CMC$ depends on temperature.
$(D)$ Micelles are macromolecular colloids.

Which of the following reactions leads to the formation of a substance in the colloidal state (in the presence of excess of $HCl$)?