$A$ colloidal system consisting of a gas dispersed in a solid is called a/an:

Zeta potential is

All colloidal solutions exhibit .......

Explain the following terms:
$(i)$ Electrophoresis
$(ii)$ Coagulation
$(iii)$ Dialysis
$(iv)$ Tyndall effect.

On addition of $1 \ mL$ solution of $10\% \ NaCl$ to $10 \ mL$ gold sol in presence of $0.025 \ g$ of starch,the coagulation is just prevented. The gold number of starch is

Among the following methods:
$(i)$ Addition of an electrolyte
$(ii)$ Electrophoresis
$(iii)$ Addition of a protective colloid
$(iv)$ Addition of an oppositely charged sol
the coagulation of a lyophobic sol can be carried out by: