Which of the following is not a negatively charged sol?

$100 \ mL$ of $0.0018\%(w/v)$ solution of $Cl^{-}$ ion was the minimum concentration of $Cl^{-}$ required to precipitate a negative sol in one $h$. The coagulating value of $Cl^{-}$ ion is $.......$ (Nearest integer).

The surface tension of a soap solution is $30 \times 10^{-3} \, N/m$. The work done to increase the surface area of a soap film from $5 \, cm \times 5 \, cm$ to $10 \, cm \times 10 \, cm$ is:

Which of the following information is incorrect?

Milk is an example of

Which of the following is a correct statement?