Which of the following does not show Tyndall effect?

The following data is obtained for coagulating a positively charged sol in $2$ hours:

Conc. of $Cl^{-}$ in $mol \cdot L^{-1}$	Result
$5 \times 10^{-5}$	Sol not precipitated
$6 \times 10^{-5}$	Sol not precipitated
$7 \times 10^{-5}$	Sol precipitated
$8 \times 10^{-5}$	Sol precipitated
$1 \times 10^{-4}$	Sol precipitated

What is the coagulating value of electrolyte for this sol?

Which property of colloids is not dependent on the charge on colloidal particles?

The Tyndall effect depends upon the

$100 \, cm^3$ of gold sol requires $10^{-4} \, g$ of gelatin to prevent coagulation when $1 \, cm^3$ of $10 \% \, NaCl$ solution is added. The gold number of gelatin is ............ .

Provide information about the colligative properties and the color of colloidal solutions.