Surface chemistry

At the equilibrium position in the process of adsorption ___________.

• ΔH > 0

• ΔH = TΔS

• ΔH > TΔS

• ΔH < TΔS

The term ‘sorption’ stands for ____________.

• absorption

• adsorption

• both absorption and adsorption

• desorption

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.

Which of the following is an example of absorption?

• Water on silica gel

• Water on calcium chloride

• Hydrogen on finely divided nickel

• Oxygen on metal surface

Method by which lyophobic sol can be protected.

• By addition of oppositely charged sol.

• By addition of an electrolyte.

• By addition of lyophilic sol.

• By boiling.

Freshly prepared precipitate sometimes gets converted to colloidal solution by ___________.

• coagulation

• electrolysis

• diffusion

• peptisation

Which of the following electrolytes will have maximum coagulating value for AgI/Ag+ sol?

• Na2S

• Na3PO4

• Na2SO4

• NaCl

Which of the following process is responsible for the formation of delta at a place where rivers meet the sea?

• Emulsification

• Colloid formation

• Coagulation

• Peptisation

Which of the following process is not responsible for the presence of electric charge on the sol particles?

• Electron capture by sol particles.

• Adsorption of ionic species from solution.

• Formation of Helmholtz electrical double layer.

• Absorption of ionic species from solution

At the equilibrium position in the process of adsorption ___________.

• ΔH > 0

• ΔH = TΔS

• ΔH > TΔS

• ΔH < TΔS