Surface chemistry

Extent of physisorption of a gas increases with ___________.

• increase in temperature.

• decrease in temperature.

• decrease in surface area of adsorbent.

• decrease in strength of van der Waals forces.

Extent of adsorption of adsorbate from solution phase increases with ________.

• increase in amount of adsorbate in solution.

• decrease in surface area of adsorbent.

• increase in temperature of solution.

• decrease in amount of adsorbate in solution.

Which of the following is not a favourable condition for physical adsorption?

• high pressure

• negative ΔH

• higher critical temperature of adsorbate

• high temperature

In physisorption adsorbent does not show specificity for any particular gas because ______________.

• involved van der Waals forces are universal.

• gases involved behave like ideal gases.

• enthalpy of adsorption is low.

• it is a reversible process.

A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is classified as ____________.

• solid solution

• gel

• emulsion

• solution

Foam is a colloidal system which consists of a dispersed phase and a dispersion medium. Indicate the dispersed phase and dispersion medium of foam, respectively.

• Liquid and liquid

• Solid and gas

• Liquid and solid

• Gas and liquid

Define adsorbate.

• The removal of adsorbed particles.

• A solid material on which adsorption occurs.

• A substance in the adsorbed phase.

• The study on the interaction phenomena on the surface.

A stable mixture of two or more liquids e.g. icecream

• emulsion

• solution

• mixture

• insoluble

The formation of micelles takes place only above

• Inversion temperature

• Boyle's temperature

• Critical temperature

• Kraft temperature

Extent of adsorption of adsorbate from solution phase increases with

• increase in amount of adsorbate in solution

• decrease in surface area of adsorbent

• decrease in amount of adsorbate in solution