Physisorption

Q.

Write the differences between Physisorption And Chemisorption.

Q.

How does temperature affect adsorption?

Q.

Why does physisorption decrease with the increase of temperature?

Q. The combination of two layers of opposite charges around the colloidal particle is called Helmholtz electrical double layer. The potential difference between the fixed layer and the diffused layer of opposite charge is called :

1. Electrode potential
2. Zeta potential
3. Adsorption potential
4. Diffused potential

Q.

Which plot is the adsorption isobar for chemisorption where x is the amount of gas adsorbed on mass m (at constant pressure) at temperature T?

1. 

2. 

3. 

4. 

Q. Method(s) for coagulation of lyophobic sols include:

1. Electrophoresis
2. Mixing two oppositely charged sols
3. Boiling
4. All of the above.

Q.

Enthalpy of adsorption for physisorption is low and positive.

1. True

2. False

Q.

If the solution of CuSO₄ in which copper rod is immersed is diluted to 100 times, the standard reduction potential

1. increases by 0.0265 V
2. increases by 0.059 V
3. decreases by 0.0265 V
4. decreases by 0.059 V

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°C. The pressure of the gas falls from 780 to 400 torr. The density of charcoal sample was 1.5 g/mL. The volume of gas (at STP) that is adsorbed per g (mL/g) of the adsorbent under the condition of experiment is (Round off upto two decimal places.)
(Use R = $\frac{1}{12}Latm/mol$)

Q. The migration of positively-charged colloidal particles under an electrical field, towards the cathode is called:

1. Cataphoresis
2. Electrosmosis
3. Sedimentation
4. Electrodialysis

Q.

In physical adsorption, the gas molecules are held on solid surface by:

1. Gravitational forces

2. Vander Waal's forces

3. Chemical forces

4. Electrostatic forces

Q. Given below are two statements. One is labelled as Assertion A and the other is
labelled as Reason R.

Assertion A: Amylose is insoluble in water.

Reason R: Amylose is a long linear molecule with more than 200 glucose units.
In the light of the above statements, choose the correct answer from the options
given below.

Q.

Rate of physisorption increases with 

1. Increase in temperature

2. Decrease in pressure

3. Decrease in temperature

4. Decrease in surface area

Q.

On increasing temperature, physical adsorption:

1. Decrease

2. Remain constant

3. Increase

4. First increases than decreases

Q. 43. Can chloral give cannizaro reaction?

Q.

Adsorption is a surface phenomenon.

1. True
2. False

Q.

What kind of forces exists between adsorbate and adsorbent in physisorption?

Q. After increasing temperature, the rate of physisorption:

1. Will decrease
2. Will increase
3. Remain same
4. Cannot say

Q. Enthalpy of adsorption for physisorption is low and positive.
Is this statement correct?

Q.

Point out the wrong statement :

Physical adsorption is characterised by

1. Attraction due to weak Vander Waal's forces

2. Irreversible nature of adsorption

3. Multimolecular adsorption layers

4. Decrease in adsorption with increase in temperature

Q. Low temperature favours physical adsorption and high temperature favours chemical adsorption.

1. True
2. False

Q.

Which one of the following is an incorrect statement for physisorption

1. It is a reversible process

2. It requires less heat of adsorption

3. It requires activation energy

4. It takes place at low temperature

Q.

What is difference between physisorption and chemisorption ?

Q. Which of the following statements is incorrect regarding a physisorption process?

1. There are van der Waal's interactions between the adsorbate and the adsorbent
2. The process predominates at low temperature
3. The process cannot proceed beyond a monolayer
4. The process is reversible

Q. Select the incorrect statement related to colloids.

1. Muddy water can be coagulated more effectively by alums as compared to $NaCl$
2. Surface tension of lyophilic colloids is less than that of dispersion medium
3. When excess of $AgN{O}_3$ is added in aqueous $KI$ solution and the sol is subjected to electrophoresis, coagulation occurs near the anode
4. Cloud bursting in atmosphere occurs due to large amount of water present in the cloud

Q. Give reasons for the following observations :

(i) Physisorption decreases with increase in temperature.

(ii) Addition of alum purifies the water.

(iii) Brownian movement provides stability to the colloidal solution.

Q. Which of the following statements is incorrect regarding physisorption?

1. It occurs because of van der Waal’s forces
2. Enthaply of adsorption $\left(\Delta H_{adsorption}\right)$ is low and positive
3. Under high pressure it results into multi molecular layer on adsorbent surface
4. More easily liquefiable gases are adsorbed readily

Q. On adding few drops of dil. $HClorFeC{l}_3$ to freshly prepared ferric hydroxide, a red coloured colloidal solution is obtained. This phenomenon is known as:

1. Peptization
2. protection
3. Dialysis
4. Dissolution

Q. Which of the following reason is incorrect for charge on colloidal particles?

1. Formation of electrical double layer
2. Preferential adsorption of ions from solution
3. Electron capture by sol particles during electro dispersion of metals
4. None of the above

Q. (a) Write the dispersed phase and dispersion medium of milk.
(b) Write one similarity between physisorption and chemisorption.
(c) Write the chemical method by which $Fe(OH{)}_3$ sol is prepared from $FeC{l}_3$.