Alum is a water purifier because it

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:

In the measurement of gold number,the useful electrolyte is

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

What is the decreasing order of coagulating power of ions for an arsenious sulphide sol based on their charge?

Colour is imparted to glass by mixing