When a sulphur sol is evaporated,sulphur is obtained. On mixing with water,the sulphur sol is not formed. The sol is

In which of the following is the Tyndall effect $NOT$ observed?

The density of gold is $19 \, g/cm^3$. If $1.9 \times 10^{-4} \, g$ of gold is dispersed in $1 \, L$ of water to form a sol of spherical gold particles of radius $10 \, nm$,find the number of gold particles per $nm^3$ in the sol.

The gold numbers of protective colloids $A, B, C$,and $D$ are $0.04, 0.004, 10$,and $40$ respectively. The order of their protective power is:

The charge of $SnO_2$-sol in alkaline and acidic medium are respectively (Hint: $SnO_2$ is amphoteric oxide).

What happens when gelatin is mixed with a gold sol?