Fruendlich Isotherm

Q. Adsorption of a gas follows the Freundlich adsorption isotherm. In the given plot, x is the mass of the gas adsorbed on mass m of the adsorbent at a pressure P.
$\frac{x}{m}\mathrm{is}\mathrm{proportional}\mathrm{to}$:

1. $P^{\frac{1}{2}}$
2. $P^{\frac{1}{4}}$
3. $P^2$
4. P

Q.

Plot of log x/m against log P is a straight line inclined at an angle of ${45}^{\circ }$. When the pressure is 0.5 atm and Freundlich parameter. K is 100, the amount of the solute adsorbed per gram of adsorbent will be (log 5 = 0.6990)

1. 1 g

2. 2 g

3. 3 g

4. 5 g

Q.

The mass of gas adsorbed, $x$, per unit mass of adsorbate, m, was measured at various pressures, $p$. A graph between $\log [\mathrm{x}/\mathrm{m}]$and $\log p$ gives a straight line with slope equal to $2$and the intercept equal to $0.4771$. The value of$[\mathrm{x}/\mathrm{m}]$at a pressure of $4$atm is:$\text{(Given}\log 3=0.4771\text{)}$

Q. $20\%$ of surface sites are occupied by $N_2$ molecules. The density of surface site is $6.023\times {10}^{14}c{m}^{-2}$ and total surface area is $1000c{m}^2$. The catalyst is heated to $300K$ while $N_2$ is completely desorbed into a pressure of $0.001atm$ and volume of $2.46c{m}^3$. Find the number of active sites occupied by each $N_2$ molecule.

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

1. 
2. 
3. 
4. 

Q. In the adsorption of a gas on solid, Freundlich isotherm is obeyed. Thus, if the slope of the plot is zero, then the extent of adsorption is:

1. directly proportional to the pressure of gas
2. inversely proportional to the pressure of the gas
3. proportional to the square of the pressure of the gas
4. independent of the pressure of the gas

Q. A plot of log $\frac{x}{m}$ versus log P for the adsorption of a gas on a solid gives a straight line with slope equal to:

1. n
2. $\frac{1}{n}$
   
3. log K
4. - log K

Q. The equation for Freundlich adsorption isotherm is

a) $\frac{x}{m}=k{p}^{\frac{1}{n}}$
b) $\left(lnx\right)=ln\left(mk\right)+\frac{1}{n}lnp$
c) $\frac{x}{m}=k{p}^{-n}$
d) Only a and b

1. a
2. b
3. c
4. d

Q. For a linear plot of $log\left(x/m\right)$ versus $logP$ in a Freundlich adsorption isotherm, which of the following statements is correct? (k and n are constants)

1. log $\left(\frac{1}{n}\right)$ appears as the intercept
2. $\frac{1}{n}$ appears as the intercept
3. Only $\frac{1}{n}$ appears as the slope
4. Both $k$ and $\frac{1}{n}$ appear in the slope term

Q. The graph plotted between log x/m (where x is the mass of adsorbate and m is the mass of the adsorbent) vs. log P was found to be a straight line. The slope and intercept of line leads to 1/n and log K values. Find the wrong statement:

1. The relation does not hold good at high pressures
2. The relation fails when chemical adsorption takes place
3. At a very low pressure, n = 1
4. On increasing the pressure, the value of n decreases

Q.

What form Freundlich Adsorption Equation will take at a higher pressure?

Q.

What is an Adsorption Isotherm? Describe Freundlich Adsorption Isotherm

Q. Freundlich adsorption isotherm is valid for chemisorption.

1. True
2. False

Q. Which of the following will not represent an adsorption process?

1. Powdered charcoal in methylene blue solution
2. Gases like $O_2,H_2,CO,C{l}_2,N{H}_{3}orS{O}_2$ is taken in a closed vessel containing charcoal.
3. Aqueous solution of raw sugar passed over beds of animal charcoal.
4. Anhydrous $CaC{l}_2$ in a desiccator

Q. Which of the following(s) will represent an adsorption process?

1. Powdered charcoal in methylene blue solution
2. Gases like $O_2,H_2,CO,C{l}_2,N{H}_{3}orS{O}_2$ is taken in a closed vessel containing charcoal.
3. Aqueous solution of raw sugar passed over beds of animal charcoal.
4. Anhydrous $CaC{l}_2$ in a desiccator

Q. Volume at NTP of oxygen required to completely burn 1 kg of coal (100% carbon):

1. $22.400$ L
2. $22.4\times {10}^3$L
3. $1.86\times {10}^3$L
4. $1000$ L

Q. I, II and III are three adsorption isotherms at three temperatures $T_1$, $T_2$ and $T_3$, where $x$ is the amount of adsorbate adsorbed per $mg$ of the adsorbent.
The temperatures $T_1$, $T_2$ and $T_3$ are in the order

1. $T_3<T_2<T_1$
2. No specific order
3. $T_1<T_2<T_3$
4. $T_1=T_2=T_3$

Q. Answer the following
1. What can be inference from Daniel cell as for me it is similar to a simple electrolysis , I mean to say what idea we got from it
2. The equivalent weight of MnSO_​​​4 is half its molecular weight when converted to MnSO_​​​4 ---> MnO_{​​​​2} + 2e , explain.
​​

Q.

Freundlich adsorption isotherm is a plot between:

1. V and T

2. x/m and p

3. P and T

4. x/m and T

Q. A sample of charcoal weighing 6.0 g was brought into contact with a gas contained in a vessel of 1 litre capacity at ${27}^{\circ }\text{C}$. The pressure of the gas falls from 700 to 400 torr. Calculate the volume of the gas (at STP) that is adsorbed per gram of the adsorbent under the condition of the experiment. The density of the charcoal compound is $1.5{\text{g cm}}^{-3}$.

Q. In Freundlich adsorption equation $\frac{x}{m}=k{p}^{1/n}$ the value of n is :

1. always greater than one
2. always equal to one
3. greater than one at low temperature and smaller than one at high temperature
4. always smaller

Q. Which is not true about the Freundlich adsorption isotherm curve?

1. At low pressures, the value of $n=1$
2. From the $ln\frac{x}{m}$ vs $P$ curve, we can find the value of n by finding the slope
3. At higher pressures, the value of $\frac{x}{m}$ is almost constant
4. At a fixed pressure, there is a decrease in physical adsorption with increase in temperature

Q.

In the graph of Freundlich isotherm which parameter is present by the slope of line?

Q. In the mathematical relation of Freundlich adsorption isotherm, the value of $\frac{1}{n}$ is $0\le \frac{1}{n}\le 1$.

1. True
2. False

Q. For a linear plot of $log\left(x/m\right)$ versus $logP$ in a Freundlich adsorption isotherm, which of the following statements is correct? (k and n are constants)

1. $\frac{1}{n}$ appears as the intercept
2. Only $\frac{1}{n}$ appears as the slope
3. log $\left(\frac{1}{n}\right)$ appears as the intercept
4. Both $k$ and $\frac{1}{n}$ appear in the slope term

Q. Freundlich adsorption isotherm is:

1. $\frac{x}{m}=K{P}^{1/n}$
2. $\frac{x}{m}=K{P}^{-n}$
3. $x=mK{P}^{1/n}$
4. all of the above

Q. What volume of air (containing 20% $O_2$ by volume) will be required to burn completely $10c{m}^3$ each of methane and acetylene.
$C{H}_4+2O_2⟶C{O}_2+2H_{2}O$
$2C_2{H}_2+5O_2⟶4C{O}_2+2H_{2}O$

Q. Adsorption of gas follows Freundlich adsorption isotherm. In the given plot, x is the mass of the gas absorbed on mass m of the adsorbent at pressure p. $\frac{x}{m}$ is proportional to:

1. $P^{\frac{1}{4}}$
2. $P^2$
3. $P$
4. $P^{\frac{1}{2}}$

Q. A graph plotted between $log\left(\frac{x}{m}\right)$ vs $logP$ ($P$ is pressure of gas in atm) shows a straight line with slope equal to $1$ and intercept equal to $0.4771$. The extent of adsorption $\left(\frac{x}{m}\right)$ of gas at the pressure $2$ atm is :

Q. Observe the given adsorption isotherm carefully and choose the correct option.
(i) These curves indicate that at a fixed temperature, there is a decrease in physical adsorption with increase in pressure.
(ii) These curves always seem to approach saturation at high pressure.
(iii) $\frac{x}{m}=k{p}^{1/n}$(n>1) is generally represented by this isotherm.
(iv) These curves indicate that at a fixed pressure, there is a decrease in physcial adsorption with increase in temperature.

1. (ii) and (iv) only
2. (ii), (iii) and (iv) only
3. (i) and (iii) only
4. All of these