# Langmuir Isotherm

## Trending Questions

**Q.**

At high pressures, Langmuir adsorption isotherm takes the form:

- xm=ap1+bP

- xm=ab

- xm=aP

- xm=ba+1aP

**Q.**

The curve showing the variation of adsorption with pressure at constant temperature is called:

An isotere

Adsorption isotherm

Adsorption isobar

All are correct

**Q.**According to Langmuir adsorption isotherm, the amount of gas adsorbed at a very high pressure:

- reaches a constant limiting value
- goes on increasing as the pressure increases
- goes on decreasing as the pressure decreases
- increases first and the decreases with an increase in pressure

**Q.**Which of the following graphs represents the Langmuir adsorption isotherm correctly?

- None of these

**Q.**

The correct expression for Langmuir adsorption isotherm is

xm=aPb

xm=aP1+bP

xm=1+aP1+bP

xm=1a+bPa

**Q.**

The correct expression for Langmuir adsorption isotherm is

- x / m = aP / 1 + bP
- x / m = 1 + aP / 1 + bP
- x / m = 1 + aP / b
- x / m = 1 / a + bP / a

**Q.**Which of the following(s) is/are the drawbacks of Freundlich adsorption isotherm?

- Isotherm deviates from straight line at high pressure.
- Isotherm deviates from straight line at low temperature
- Isotherm is applicable only when adsorbate forms unimolecular layer on adsorbent surface
- Isotherm is applicable only when adsorbate forms multi-layer layer on adsorbent surface

**Q.**A gas undergoes physical adsorption on a surface and follows the given Freundlich adsorption isotherm equation xm=kp0.5

Adsorption of the gas increase with

- decrease in p and decrease in T
- increase in p and increase in T
- decrease in p and increase in T
- increase in p and decrease in T

**Q.**2.0 g of charcoal is placed in a 100 mL solution of 0.05 M CH3COOH to form an adsorbed monoacidic layer of acetic acid molecules and thereby the molarity of CH3COOH reduces to 0.49 M. The surface area of charcoal is 3×102 m2g−1. The surface area of charcoal used by each molecule of acetic acid is:

- 1.0×10−19 cm2
- 1.0×10−13 cm2
- 1.0×10−14 cm2
- 1.0×10−18 cm2

**Q.**

Does the chemical adsorption increase or decrease when the surface area of the adsorbent increases?

**Q.**The langmuir adsorption isotherm is deduced using the assumption:

- The adsorption sites are equivalent in their ability to adsorb the particles
- The heat of adsorption varies with coverage
- The adsorption molecules interact with each other
- The adsorption takes place in multiplayers

**Q.**

The relation between extent of adsorbtion (x/m) and pressure at constant temperature is called as:

isobar

isotherm

isomer

isochore

**Q.**The langmuir adsorption isotherm is deduced using the assumption:

- The adsorption sites are equivalent in their ability to adsorb the particles
- The heat of adsorption varies with coverage
- The adsorption molecules interact with each other
- The adsorption takes place in multiplayers

**Q.**According to Langmuir adsorption isotherm, the amount of gas adsorbed at a very high pressure:

- reaches a constant limiting value
- goes on increasing as the pressure increases
- goes on decreasing as the pressure decreases
- increases first and the decreases with an increase in pressure

**Q.**Why both Freundlich and Langmuir adsorption isotherms hold good at high pressure and fail at low pressure?

**Q.**For adsorption of a gas on a solid, the plot of logxm Vs log p would be

- Linear with slope 1n
- Parabola with slope 1n
- Linear with slope log K
- Hyperbola with slope log K

**Q.**According to Langmuir adsorption isotherm, the amount of gas adsorbed at a very high pressure:

- reaches a constant limiting value
- goes on increasing as the pressure increases
- goes on decreasing as the pressure decreases
- increases first and the decreases with an increase in pressure

**Q.**Graph between log(xm) and logp is a straight line at an angle 45∘ with intercept on y-axis 0, 3010. Calculate the amount of gas adsorbed in gram per gram of the adsorbent when pressure is 0.2 atm.

- 0.4
- 0.6
- 0.8
- 0.2

**Q.**At high pressure, Langmuir adsorption isotherm takes the form:

- xm=aP1+bP
- xm=ab
- xm=aP
- xm=ba+1aP

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

- xm=f(T) at constant P
- P=f(T) at constant (xm)
- xm=P×T
- xm=f(P) at constant T

**Q.**On basis of which theory Langmuir derived isotherm equation ?

- Collosion theory
- Kinetic theory of gases
- Thermodynamics
- Wave mechanic theory

**Q.**In Freundlich Adsorption isotherm, the value of 1/

*n*is :

- 1 in case of physical adsorption
- 1 in case of chemisorption
- between 0 and 1 in all cases
- between 2 and 4 in all cases

**Q.**The equation for Freundlich adsorption isotherm is:

- x=mkp1/n
- xm=kp−n
- All of these
- xm=kp1/n

**Q.**Write an equation for the pressure exerted by a gas in a container.

**Q.**calculate the vant hoff factor for a binary solute undergoing 100% dissociation

**Q.**Select the correct option for the graph above.

- T1>T2>T3
- T1=T2=T3
- T1<T2<T3
- T1>T2<T3

**Q.**At high pressures, Langmuir adsorption isotherm takes the form:

- xm=ap1+bp

- xm=ap

- mx=ba+1ap

- xm=ab

**Q.**When log (xm) is plotted against log P, we get a straight line with slope 1n .

- True
- False

**Q.**Assertion :Langmuir adsorption is a single-layer phenomenon. Reason: It is due to van der Waals forces.

- Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
- Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
- Assertion is correct but Reason is incorrect
- Assertion is incorrect but Reason is correct

**Q.**1 g of activated charcoal has a surface area 103m2. If complete monolayer coverage is assumed and effective surface area of NH3 molecules is 0.129nm2, how much NH3 in moles at STP could be adsorbed on 25 g of charcoal (write answer as the nearest integer after multiplying with 10)?