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WorksheetsSurface Chemistry : Level 3
Total questions: 10
Worksheet time: 20mins
Which one of the following is an example of adsorption?
ammonia in contact with water
ammonia in contact with hydrogen gas
silica gel in contact with water vapors
None of above
In Freundlich Adsorption isotherm, the value of 1/n is
1 in case of physical adsorption
1 in case of chemical adsorption
Between 0 and 1 in all cases
Less than 0 all cases
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
Rate of physical adsorption increase with
Increase in temperature
Decrease in pressure
Decrease in temperature
Decrease in surface area
The Langmuir adsorption isotherm is deduced using the assumption
The adsorbed molecules interact with each other
The adsorption takes place in multilayers
The adsorption sites are equivalent in their ability to adsorb the particles
The heat of adsorption varies with coverage
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
In Langmuir's model of adsorption of a gas on a solid surface
the adsorption at a single site on the surface may involve multiple molecules at the same time
the mass of gas striking a given area of surface is proportional to the pressure of the gas
the mass of gas striking a given area of surface is independent of the pressure of the gas
the rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered
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
Activated charcoal is used to remove coloring matter from pure substances. It works by___________.
Sorption
Absorption
Adsorption
Bleaching
