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WorksheetsSURFACE CHEMISTRY - ADSORPTION
Total questions: 20
Worksheet time: 10mins
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?
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 > H2
CO2 > NH3 > H2 > CH4
NH3 > CO2 > H2 > CH4
NH3 > CO2 > CH4 > H2
Which of the following statements is incorrect regarding physisorption?
It occurs because of van der Walls forces
More easily liquefiable gases are adsorbed readily
Under high pressure it results into multimolecular layer on adsorbent surface
Enthalpy of adsorption (ΔHadsorption) is low and positive
A plot of log x/m versus log p for the adsorption of a gas on a solid gives a straight line with slope equal to
n
1/n
log K
- log K
The extent of adsorption of a gas on a solid depends on ______.
temperature of the gas
pressure of the gas
nature of the gas
all are correct
Which one of the following characteristics is associated with adsorption?
ΔG and ΔH are negative but ΔS is positive
ΔG and ΔS are negative but ΔH is positive
ΔG is negative but ΔH and ΔS are positive
ΔG, ΔH and ΔS all are negative
For a linear plot of log(x/m) versus log p in a Freundlich adsorption isotherm, which of the following statements is correct? (k and n are constants)
1/n appears as the intercept
Only 1/n appears as the slope
log(1/n) appears as the intercept
Both k and 1/n appear in the slope term
A particular adsorption process has the following characteristics:
(i) It arises due to van der Waals forces and
(ii) it is reversible.
Identify the correct statement that describes the above adsorption process
Adsorption is monolayer.
Adsorption increases with increase in temperature
Enthalpy of adsorption is greater than 100 kJ mol–1.
Energy of activation is low.
Which of the following interface cannot be obtained
liquid-liquid
solid-liquid(
liquid-gas
gas-gas
The term ‘sorption’ stands for ___________
absorption
adsorption
both absorption and adsorption
desorption
Physical adsorption of a gaseous species may change to chemical adsorption with ______________
decrease in temperature
increase in temperature
increase in surface area of adsorbent
decrease in surface area of adsorbent
Example for physisorption
adsorption of O2 on tungsten
adsorption of H2 on nickel
adsorption of N2 on mica
adsorption of C2H5OH on nickel
