Gold sol is not:

$A$ $42.12 \% (w/v)$ solution of $NaCl$ causes precipitation of a certain sol in $10 \, hours$. The coagulating value of $NaCl$ for the sol is $.....$
[Given : Molar mass : $Na = 23.0 \, g \, mol^{-1} ; Cl = 35.5 \, g \, mol^{-1}]$

Photographic plates are prepared by coating an emulsion of which of the following in gelatin?

Which of the following ionic substances will be most effective in precipitating negatively charged sulphur sol? (All compounds are $100\%$ ionized)

Which one of the following is a lyophilic colloid?

Micelles are $....$.