Langmuir Isotherm

Q.

At high pressures, Langmuir adsorption isotherm takes the form:

1. $\frac{x}{m}=\frac{ap}{1+bP}$
   
2. $\frac{x}{m}=\frac{a}{b}$
   
3. $\frac{x}{m}=aP$
   
4. $\frac{x}{m}=\frac{b}{a}+\frac{1}{aP}$
   

Q.

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

1. An isotere

2. Adsorption isotherm

3. Adsorption isobar

4. All are correct

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

1. reaches a constant limiting value
2. goes on increasing as the pressure increases
3. goes on decreasing as the pressure decreases
4. increases first and the decreases with an increase in pressure

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

1. 
2. 
3. 
4. None of these

Q.

The correct expression for Langmuir adsorption isotherm is

1. $\frac{x}{m}=\frac{aP}{b}$

2. $\frac{x}{m}=\frac{aP}{1+bP}$

3. $\frac{x}{m}=\frac{1+aP}{1+bP}$

4. $\frac{x}{m}=\frac{1}{a}+\frac{bP}{a}$

Q.

The correct expression for Langmuir adsorption isotherm is

1. x / m = aP / 1 + bP
2. x / m = 1 + aP / 1 + bP
3. x / m = 1 + aP / b
4. x / m = 1 / a + bP / a

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

1. Isotherm deviates from straight line at high pressure.
2. Isotherm deviates from straight line at low temperature
3. Isotherm is applicable only when adsorbate forms unimolecular layer on adsorbent surface
4. 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 $\frac{x}{m}=k{p}^{0.5}$
Adsorption of the gas increase with

1. decrease in $p$ and decrease in $T$
2. increase in $p$ and increase in $T$
3. decrease in $p$ and increase in $T$
4. increase in $p$ and decrease in $T$

Q. $2.0\text{g}$ of charcoal is placed in a $100\text{mL}$ solution of $0.05\text{M}C{H}_{3}COOH$ to form an adsorbed monoacidic layer of acetic acid molecules and thereby the molarity of $C{H}_{3}COOH$ reduces to $0.49\text{M}$. The surface area of charcoal is $3\times {10}^2{\text{m}}^2{\text{g}}^{-1}$. The surface area of charcoal used by each molecule of acetic acid is:

1. $1.0\times {10}^{-19}{\text{cm}}^2$
2. $1.0\times {10}^{-13}{\text{cm}}^2$
3. $1.0\times {10}^{-14}{\text{cm}}^2$
4. $1.0\times {10}^{-18}{\text{cm}}^2$

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:

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

Q.

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

1. isobar

2. isotherm

3. isomer

4. isochore

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

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

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

1. reaches a constant limiting value
2. goes on increasing as the pressure increases
3. goes on decreasing as the pressure decreases
4. 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 $log\frac{x}{m}$ Vs log p would be

1. Linear with slope $\frac{1}{n}$
2. Parabola with slope $\frac{1}{n}$
3. Linear with slope log K
4. Hyperbola with slope log K

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

1. reaches a constant limiting value
2. goes on increasing as the pressure increases
3. goes on decreasing as the pressure decreases
4. increases first and the decreases with an increase in pressure

Q. Graph between $\log \left(\frac{x}{m}\right)$ and $\log p$ is a straight line at an angle ${45}^{\circ }$ with intercept on y-axis $0,3010$. Calculate the amount of gas adsorbed in gram per gram of the adsorbent when pressure is $0.2atm$.

1. $0.4$
2. $0.6$
3. $0.8$
4. $0.2$

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

1. $\frac{x}{m}=\frac{aP}{1+bP}$
2. $\frac{x}{m}=\frac{a}{b}$
3. $\frac{x}{m}=aP$
4. $\frac{x}{m}=\frac{b}{a}+\frac{1}{aP}$

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

1. $\frac{x}{m}=f\left(T\right)$ at constant $P$
2. $P=f\left(T\right)$ at constant $\left(\frac{x}{m}\right)$
3. $\frac{x}{m}=P\times T$
4. $\frac{x}{m}=f\left(P\right)$ at constant $T$

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

1. Collosion theory
2. Kinetic theory of gases
3. Thermodynamics
4. Wave mechanic theory

Q. In Freundlich Adsorption isotherm, the value of 1/n is :

1. $1$ in case of physical adsorption
2. $1$ in case of chemisorption
3. between $0$ and $1$ in all cases
4. between $2$ and $4$ in all cases

Q. The equation for Freundlich adsorption isotherm is:

1. $x=mk{p}^{1/n}$
2. $\frac{x}{m}=k{p}^{-n}$
3. All of these
4. $\frac{x}{m}=k{p}^{1/n}$

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.

1. $T_1>T_2>T_3$
2. $T_1=T_2=T_3$
3. $T_1<T_2<T_3$
4. $T_1>T_2<T_3$

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

1. $\frac{x}{m}=\frac{\mathrm{ap}}{1+\mathrm{bp}}$
   
2. $\frac{x}{m}=\mathrm{ap}$
   
3. $\frac{m}{x}=\frac{b}{a}+\frac{1}{\mathrm{ap}}$
   
4. $\frac{x}{m}=\frac{a}{b}$
   

Q. When log $\left(\frac{x}{m}\right)$ is plotted against $logP$, we get a straight line with slope $\frac{1}{n}$ .

1. True
2. False

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

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q. $1$ g of activated charcoal has a surface area ${10}^3{m}^2$. If complete monolayer coverage is assumed and effective surface area of $N{H}_3$ molecules is $0.129n{m}^2$, how much $N{H}_3$ in moles at STP could be adsorbed on $25$ g of charcoal (write answer as the nearest integer after multiplying with 10)?