Surface Chemistry Test

Result

Surface Chemistry Test - 9

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Weekly Quiz Competition

Question 1
1 / -0.25

When a graph is plotted between log x/m and log p, it is straight line With an angle 45 °and intercept 0.3010 on y-axis. If initial pressure is 0.3 atm, what will be the amount of gas adsorbed per gm of adsorbent :

A
0.4

B
0.6

C
0.8

D
0.1

Solution
Question 2
1 / -0.25

Which of the following statements about physical adsorption is not correct ?

A
It is usually monolayer

B
It is reversible in nature

C
It involves van der Weals interactions between adsorbent and adsorbate

D
It involves small value of adsorption

Solution

Physical adsorption is a multilayer phenomenon
Question 3
1 / -0.25

Following is the variation of physical adsorption with temperature:

A

B

C

D

Solution

Rate of physical adsorption gradually decreases with increase the temperature.
Question 4
1 / -0.25

Finally divided catalyst has greater surface area and has greater catalytic activity then the compact solid. If a total surface area of 6291456 cm is required for adsorption of gaseous reaction in a catalysed reaction, then how many splits should be made of cube exactly 1 cm in length.

A
60

B
80

C
20

D
22

Solution
Question 5
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Which of the following is not characteristic of chemisorption?

A
it is irreversible                                      `

B
it is specific

C
it is multilayer phenomenon

D
heat of adsorption of about –400 kJ

Solution

Chemical adsorption is a mono layer phenomenon
Question 6
1 / -0.25

A colloidal solution can be purified following the method of

A
4 dialysis

B
peptization

C
filtration

D
oxidation

Solution

The Correct answer is option A
A colloidal solution can be purified by the following methods - Dialysis, Electro-dialysis and Ultrafiltration.
Question 7
1 / -0.25

Gold number of a lyophilic sol is such property that:

A
the larger its value, the greater is the peptising power

B
the lower its value, the greater is the peptising power

C
the lower its value, the greater is the protecting power

D
the larger its value, the greater is the protecting power

Solution

Lower is the value gold number; greater will be the protecting power
Question 8
1 / -0.25

100 mL of a colloidal solution is completely precipitated by addition of 5 mL of 1 M Nacl solution . Calculate the coagulation value of Nacl .

A
200

B
100

C
50

D
25

Solution

The correct answer is Option C.
Since, coagulation value is defined as the millimoles of an electrolyte that must be added to 1L of solution for coagulation to take place.
No. of millimoles in 5 ml of 1 M NaCl
                    = (1/1000) * 5
                    = 0.005 moles
                    = 5 moles
No. of millimoles in 100 ml of NaCl
                    = (5*100)/10
                    = 50 moles
Question 9
1 / -0.25

At CMC, the surfactant molecules :

A
Decomposes

B
Become completely soluble

C
Associate

D
Dissociate

Solution

The correct answer is Option C.
In colloidal solution, critical micelle concentration (CMC) is the concentration of surfactants above which micelles form and all additional surfactants added to the system go to micelles, this is because association occurs at CMC.
Question 10
1 / -0.25

Some type of gels like gelatin loose water slowly. The process is known as :

A
Synerisis

B
Thixotropy

C
Peptisation

D
Imbibition

Solution

The correct answer is Option A.
Syneresis is the extraction or expulsion of a liquid from a gel. For example, when lymph drains from a contracting clot of blood.
Thixotropy is a shear thinning property. Certain gels or fluids that are thick (viscous) under static conditions will flow (become thin, less viscous) over time when shaken, agitated or otherwise stressed.
Peptization is the dispersion of a freshly precipitated material into a colloidal solution by action of an electrolyte.
Imbibition is the absorption of a liquid by a solid or gel.