SURFACE CHEMISTRY - ADSORPTION

If x is amount of adsorbate and m is the amount of adsorbent, which of the following relations is not related to adsorption process?

• x/m = f(p) at constant T

• x/m = f(p) at constant T

• p = f(T) at constant (x/m)

• x/m = p × T

Digestion of food is difficult during fever because

• The digestive system expands

• The pressure inside the body decreases with respect to outside pressure

• The volume of the tracts contracts

• Increase in temperature results in low absorption

Which gas is adsorbed strongly be charcoal

• CO

• N₂

• H₂

• O₂

Which plot is the adsorption isobar for chemisorption x is the amount of gas adsorbed on the mass m at temperature T at constant pressure?

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Chemisorption is

• multimolecular nature

• reversible

• often highly specific and directional

• not specific

Adsorption is accompanied by

• decrease in entropy of the system

• decrease in enthalpy of the system

• TΔS for the process is negative

• all of the above

Which of the following is not applicable for chemisorption

• its heat of adsorption is high

• its takes place at high temperature

• it is reversible

• it forms unimolecular layer

Rate of physisorption increases with temperature

• decrease in temperature

• increase in temperature

• decrease in pressure

• decrease in surface area

Which one of the following is an example of adsorption?

• ammonia in contact with water

• anhydrous CaCl2 with water

• silica gel in contact with water vapours

• all of these

The volume of gases H2, CH4, CO2 and NH3 adsorbed by 1 gm charcoal at 293 K can be given in the order?

• CH₄ > CO₂ > NH₃ > H_{2 }

• CO₂ > NH₃ > H₂ > CH₄

• NH₃ > CO₂ > H₂ > CH₄

• NH₃ > CO₂ > CH₄ > H₂