Surface Chemistry I

Adsorption is a

• Bulk phenomena

• Surface phenomena

• Both

• None of these

Rough surface of an adsorbent has

• More porus

• Non porus

• More active centres

• Less active centres

In gas masks which substance is used to absorb toxic gases and vapours?

• Coal powder

• Animal charcoal

• Wood charcoal

• Activated charcoal

Absorption is a

• Bulk phenomena

• Surface phenomena

• Both

• None of these

Which can be used as an adsorbent for removal of moisture and controlling humidity in room?

• Silicon

• Clay

• Silica

• Ceramic

The amount of heat evolved when one mole of a gas is adsorbed on a solid surface is called as

• Molar enthalpy of absorption

• Molar enthalpy of desorption

• Molar enthalpy of adsorption

• entropy of adsorption

Physisorption is held by

• Covalent forces

• Chemical forces

• Vander Waal forces

• Centrifugal forces

Chemisorption is held by

• Covalent bond

• Chemical forces

• Van der Waal forces

• Centrifugal

Surface compound formation takes place in

• Physical adsorption

• Desorption

• Chemical adsorption

• Sorption

When the concentration of adsorbate is more on the surface than the bulk of the adsorbent it is called as

• Positive adsorption

• Negative adsorption

• Positive absorption

• Negative absorption