Surface Chemistry Test

Result

Surface Chemistry Test - 43

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Which of the following statements is incorrect regarding physical adsorption?

A
It occurs because of van der Waal's forces.

B
More easily liquefiable gases are adsorbed readily.

C
Under high pressure it results into multi molecular layer on adsorbent surface.

D
Enthalpy of adsorption $$(\Delta { H }_{ adsorption })$$ is low and positive.

Solution

Properties of physical adsorption-
$$i)$$ It occurs through the formation of bonds by van der Waal's forces.
$$ii)$$ Enthalpy of adsorption is low and positive.
$$iii)$$ Under high pressure, it results in a multilayer phenomenon.
Hence, Option $$B$$ is the correct answer.
Question 2
1 / -0

The dispersed phase in colloidal iron (III) hydroxide and coltoidal gold is positively and negatively charged, respectively. Which of the following statements is not correct?

A
Sodium sulphate solution causes coagulation in both sols

B
Magnesium chloride solution coagulates, the gold sol more readily than the iron (III) hydroxide sol.

C
the processes of electrophoresis provide charge on both the sols

D
Colloidal iron is coagulated by $$Mg^{+2}$$ and coltoidal gold is coagulated by $$Cl^{-}$$

Solution

Since, dispersed phase of colloidal iron $$(III)$$ hydroxide is positively charged, colloidal iron can't be coagulated by positive ion $$Mg^{+2}$$ because positively charged iron hydroxide colloidals repel $$Mg^{2+}$$ ion. In the same way, negatively charged gold colloids can't be coagulated by anion $$Cl^{\circleddash}$$. Therefore, the statement D is not correct.
Question 3
1 / -0

Which of the following gases is adsorbed to maximum extent on the given surface?

A
$$NH_3$$

B
$$H_2$$

C
$$N_2$$

D
$$O_2$$

Solution

The amount of gas adsorbed depends upon the nature of the gas.
$$\text{Extent of adsorption} \propto \text{Critical temparature}$$
The critical temperature follows the order:
$$NH_3>N_2>O_2>H_2$$
Therefore option $$A$$ is the correct answer.
Question 4
1 / -0

Which metal sol can not be prepared by Bredig's arc method?

A
$$K$$

B
$$Cu$$

C
$$Au$$

D
$$Pt$$

Solution

Bredig's are method is suitable for the preparation of collodial solution of metals lite gold, silver, copper and platinum etc. It is not for the very reactive metals like $$K,Na$$.
Ans :- Option A.
Question 5
1 / -0

The adsorption of a gas, on a solid surface, varies with pressure of the gas in which of the following manner?

A
Slow fast independent of the pressure

B
Fast slow independent of the pressure

C
Independent of the pressure slow fast

D
Independent of the pressure fast slow

Solution

The adsorption of a gas on the solid surface varies in the following manner.
Fast $$\longrightarrow $$ Slow $$\longrightarrow $$ independent of pressure.
Question 6
1 / -0

In which condition, adsorption will not take place?

A
When $$\Delta H$$ is negative

B
When $$\Delta H $$ is positive $$\Delta S $$ is positive

C
When $$\Delta H $$ is positive and $$\Delta S $$ is negative

D
When $$\Delta G $$ is negative.

Solution

Adsorption takes place only when $$\Delta G <0$$ i.e. $$\Delta H- T \Delta S <0$$.
So, if $$\Delta H$$ is positive and $$\Delta S$$ is negative then $$\Delta H- T \Delta S$$ will always be positive. So adsorption will not take place.
Question 7
1 / -0

Which types of molecules form micelle?

A
non polar molecules

B
polar molecules

C
sufactant molecules

D
Any of the above

Solution

Micelle Formation is a response to the amphipathic nature of fatty acids, meaning that they contain both hydrophilic and hydrophobic regions.
Micelle is an aggregate of surfactant molecules dispersed in a liquid colloid.
Question 8
1 / -0

Gold sol is an electronegative sol. The amount of electrolyte required to coagulate a certain amount of gold sol is minimum in the case of:

A
$$CaCl_2$$

B
$$NaCl$$

C
$$AlCl_3$$

D
$$Na_2SO_4$$

Solution
Question 9
1 / -0

When the temperature is lowered and pressure is raised, the adsorption of a gas on a solid?

A
Decreases

B
Increases

C
Remains unaffected

D
Decreases first then increases

Solution

When the temperature is lowered, there will be a decrease in kinetic energy of the molecules of a gas. Hence, adsorption increases.
When the pressure increases, adsorption of a gas also increases.
Hence, the correct option is B.
Question 10
1 / -0

The charcoal maintained at $$100^oC$$ adsorbs

A
$$Ne$$ and $$Kr$$

B
$$He$$ and $$Ar$$

C
$$Ar, Kr$$ and $$Xe$$

D
$$He$$ and $$Ne$$

Solution

Except $$He$$, all other noble gases are adsorbed by coconut charcoal at low temperatures. The extent of adsorption increases as the atomic size of the noble gas increases. As the temperature increases the extent of adsorption decreases.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Surface Chemistry Test - 43

Result

Surface Chemistry Test - 43

Score

-

Rank

-

SHARING IS CARING

Question 1

It occurs because of van der Waal's forces.

More easily liquefiable gases are adsorbed readily.

Under high pressure it results into multi molecular layer on adsorbent surface.

Enthalpy of adsorption $$(\Delta { H }_{ adsorption })$$ is low and positive.

Solution

Question 2

Sodium sulphate solution causes coagulation in both sols

Magnesium chloride solution coagulates, the gold sol more readily than the iron (III) hydroxide sol.

the processes of electrophoresis provide charge on both the sols

Colloidal iron is coagulated by $$Mg^{+2}$$ and coltoidal gold is coagulated by $$Cl^{-}$$

Solution

Question 3

$$NH_3$$

$$H_2$$

$$N_2$$

$$O_2$$

Solution

Question 4

$$K$$

$$Cu$$

$$Au$$

$$Pt$$

Solution

Question 5

Slow fast independent of the pressure

Fast slow independent of the pressure

Independent of the pressure slow fast

Independent of the pressure fast slow

Solution

Question 6

When $$\Delta H$$ is negative

When $$\Delta H $$ is positive $$\Delta S $$ is positive

When $$\Delta H $$ is positive and $$\Delta S $$ is negative

When $$\Delta G $$ is negative.

Solution

Question 7

non polar molecules

polar molecules

sufactant molecules

Any of the above

Solution

Question 8

$$CaCl_2$$

$$NaCl$$

$$AlCl_3$$

$$Na_2SO_4$$

Solution

Question 9

Decreases

Increases

Remains unaffected

Decreases first then increases

Solution

Question 10

$$Ne$$ and $$Kr$$

$$He$$ and $$Ar$$

$$Ar, Kr$$ and $$Xe$$

$$He$$ and $$Ne$$

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.