Adsorption and Absorption

Q.

Difference Between External Indicators and Internal Indicators

Q. Gases$H_{2}He{O}_2{N}_2$
$\text{Critical temperature(K)}33.25.3154.3126$
From the above data what whould be the order of liquefaction of these gases?
Start writing the order from the gas liquefying first.

1. $H_2,He,O_2,N_2$
2. $He,O_2,H_2,N_2$
3. $N_2,O_2,He,H_2$
4. $O_2,N_2,H_2,He$

Q.

Which of the following is an example of absorption?

1. Water on silica gel

2. Water on calcium chloride

3. Hydrogen on finely divided nickel

4. Oxygen on a metal surface

Q. Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Activated charcoal adsorbs $S{O}_2$ more efficiently than $C{H}_4.$
Reason R: Gases with lower critical temperatures are readily adsorbed by activated charcoal.
In the light of the above statements, choose the correct answer from the options given below.

1. A is not correct but R is correct.
2. A is correct but R is not correct.
3. Both A and R are correct and R is the correct explanation of A.
4. Both A and R are correct but R is NOT the correct explanation of A.

Q.

Amongst the following statements regarding adsorption, those that are valid are:

(a) $\Delta H$ becomes less negative as adsorption proceeds.

(b) On a given adsorbent, ammonia is adsorbed more than nitrogen gas.

(c) On adsorption, the residual force acting along the surface of the adsorbent increases.

(d) With an increase in temperature, the equilibrium concentration of adsorbate increases.

1. $\left(\mathrm{b}\right)\mathrm{and}\left(\mathrm{c}\right)$

2. $\left(\mathrm{c}\right)\mathrm{and}\left(\mathrm{d}\right)$

3. $\left(\mathrm{a}\right)\mathrm{and}\left(\mathrm{b}\right)$

4. $\left(\mathrm{d}\right)\mathrm{and}\left(\mathrm{a}\right)$

Q.

Define chromatogram.

Q. 12. Precipitate of Mg(OH)2 attains blue colour when precipitated in the presence of magneson reagent .How and why?

Q.

Why is the enthalpy of adsorption negative?

Q.

Tick the most appropriate answer:

(iii) Which silver nitrate solution reacts with sodium chloride solution, a precipitate silver chloride is formed. The colour of precipitate is

1. white

2. dirty green

3. yellow

4. brown

Q. Chemisorption decreases with increase in pressure. Why?

Q.

Distinguish between the meaning of adsorption and absorption. Give one example in each case ?

Q.

What is the enthalpy of adsorption?

Q. When glycerol is heated with khso4 , the reaction mechanism will be

Q. What happens when powdered activated charcoal, added to methylene blue solution in water, is filtered?

1. The mixture turns blue
2. The mixture turns black
3. Clear aqueous solution obtained
4. None of the above

Q. 36.Number of moles of AgCl precipitated when excess of silver nitrate solution is added to A, B and C respectively A=CoCl3 .6NH3 (yellow) B=CoCl3 .5NH3 ( purple ) C=CoCl3.4NH3 ( violet )

Q.

What does adsorbate mean?

Q. The properties of physical adsorption are:

1. Absorbate is held to the adsorbent by weak hydrogen bonds
2. As the temperature increases, adsorption decreases
3. A multilayer is possible
4. Adsorption is reversible
5. It is more specific

Q. 22. WHAT IS OXIMERCURATION-DEMERCURATION REACTION?

Q.

The technique of chromatography is based on the difference in solubility of the substances in the solvent and the rates at which the substances are adsorbed on a suitable adsorbent.

1. True
2. False

Q. In chromatography, when the fixed phase is solid, the basis of separation is

1. Adsorption
2. Absorption
3. Solubility
4. Partition

Q.

Which of the following 0.10m aqueous solutions will cause highest depression in freezing point?

1. Glucose

2. Aluminium sulphate.

3. Sucrose

4. Potassium Chloride

Q.

Define adsorption.

Q.

The mixture of compounds A and B is passed through a column of $A{l}_2{O}_3$ by using alcohol as eluant. Compound A is eluted in preference to compound B. Which of the compounds A or B, is more readily adsorbed on the column?

Q.

Which of the following is a colligative property?

1. Molality

2. Relative lowering of vapour pressure

3. Viscosity

4. Surface tension

Q.

Thin layer chromatography is______.

1. Partition chromatography

2. Adsorption chromatography

3. Electrical mobility of ionic species

4. None of the above

Q.

What are emulsifiers and what are they used for?

Q.

What is an adsorbent material?

Q.

Sticking of one substance at the surface of another is called

1. Absorption

2. Chemisorption

3. Desorption

4. Adsorption

Q. 53. In the cell reaction 2 Cu(s) 2Ag (aq) Cu (aq) 2Ag(s) + + + +, E 0 cell = 0.46 V. By doubling the concentration of Cu2+, E0 cell is: (a) doubled (b) halved (c) increases but less than double (d) decreases by a small fraction

Q. Write the difference between absorption and adsorption.