The $Purple \ of \ Cassius$ is $......$.

Which of the following electrolytes is least effective in causing flocculation of ferric hydroxide sol?

Lyophilic sols are

The gold numbers of gelatin,haemoglobin,and sodium acetate are $0.005$,$0.05$,and $0.7$ respectively. Their protective power will be in the order:

Identify the correct statements from the following :
$I$. Sulphur sol is an example of a multimolecular colloid.
$II$. Tyndall effect is observed when the diameter of the dispersed particles is not much smaller than the wavelength of the light used.
$III$. The process of removing a dissolved substance from a colloidal solution by means of diffusion through a suitable membrane is called peptisation.
$IV$. Eosin,gelatin are examples of negatively charged sols.

Ferric chloride is applied to stop bleeding from a cut because: