jee main chemistry important questions | Purification And Characterization Of Organic Compounds

Q 1 :

The technique used for purification of steam volatile water immiscible substances is: [2024]

frictional distillation
fractional distillation under reduced pressure
distillation
steam distillation

1

2

3

4

(4)

Process of steam distillation is used for its purification. The vapours of steam and the liquid compound come out of the heated flask and are condensed and collected in a separate flask. As the liquid is immiscible with water (in liquid phase), these two form separate layers and are separated using a separating funnel.

Q 2 :

Chromatographic technique/s based on the principle of differential adsorption is/are
A. Column chromatography
B. Thin layer chromatography
C. Paper chromatography

Choose the most appropriate answer from the options given below: [2024]

B only
A only
A and B only
C only

1

2

3

4

(3)

On the basis of differential adsorption, chromatographic techniques are of two types:
Column chromatography and thin layer chromatography.

Q 3 :

Which among the following purification methods is based on the principle of "Solubility" in two different solvents? [2024]

Column Chromatography
Sublimation
Distillation
Differential Extraction

1

2

3

4

(4)

An organic compound present in an aqueous solution along with other ionic impurities is separated by the principle of differential extraction. For this method a suitable organic solvent is chosen which is immiscible in water. This solvent is added to the aqueous solution containing the organic compound. Organic compound has more solubility in the organic solvent than in water, hence is transferred from water to the organic solvent. Other ionic impurities in aqueous solution remain in water.

Q 4 :

‘Adsorption’ principle is used for which of the following purification method? [2024]

Chromatography
Sublimation
Extraction
Distillation

1

2

3

4

(1)

Adsorption chromatography is based on the fact that different compounds are adsorbed on an adsorbent to different degrees.

Q 5 :

Match List I with List II

LIST I (Technique) LIST II (Application)

A. Distillation I. Separation of glycerol from spent-lye

B. Fractional distillation II. Aniline - Water mixture

C. Steam distillation III. Separation of crude oil fractions

D. Distillation under reduced pressure IV. Chloroform - Aniline

Choose the correct answer from the options given below: [2024]

A-IV, B-I, C-II, D-III
A-IV, B-III, C-II, D-I
A-I, B-II, C-IV, D-III
A-II, B-III, C-I, D-IV

1

2

3

4

(2)

Separation technique	Application
Distillation	Chloroform (b.p 334 K) and aniline (b.p. 457 K)
Fractional distillation	Different fractions of crude oil in the petroleum industry are separated by fractional distillation.
Steam distillation	Aniline is separated by this technique from aniline–water mixture
Distillation under reduced pressure	Glycerol is separated from spent-lye in the soap industry.

Q 6 :

The fragrance of flowers is due to the presence of some steam volatile organic compounds called essential oils. These are generally insoluble in water at room temperature but are miscible with water vapour in vapour phase. A suitable method for the extraction of these oils from the flowers is: [2024]

distillation
crystallisation
steam distillation
distillation under reduced pressure

1

2

3

4

(3)

Steam distillation is applied to separate substances which are steam volatile and are immiscible with water. Thus essential oils are extracted from flowers using this technique.

Q 7 :

The adsorbent used in adsorption chromatography is/are

A. silica gel
B. alumina
C. quick lime
D. magnesia

Choose the most appropriate answer from the options given below: [2024]

C and D only
A only
A and B only
B only

1

2

3

4

(3)

Silica gel and alumina are used as adsorbents in adsorption chromatography.

Q 8 :

Which of the following statements are correct?

(A) Glycerol is purified by vacuum distillation because it decomposes at its normal boiling point.
(B) Aniline can be purified by steam distillation as aniline is miscible in water.
(C) Ethanol can be separated from ethanol-water mixture by azeotropic distillation because it forms azeotrope.
(D) An organic compound is pure, if mixed M.P. is remained the same.

Choose the most appropriate answer from the options given below: [2024]

B, C, D only
A, C, D only
A, B, C only
A, B, D only

1

2

3

4

(2)

Aniline can be purified by steam distillation as aniline is immiscible in water.

Q 9 :

The correct statements among the following, for a "chromatography" purification method is: [2024]

Non-polar compounds are retained at the top and polar compounds come down in column chromatography.
Organic compounds run faster than solvent in the thin layer chromatographic plate.
$R_{f}$ of a polar compound is smaller than that of a non-polar compound.
$R_{f}$ is an integral value.

1

2

3

4

(3)

More polar compounds are absorbed more in chromatography hence have lower $R_{f}$ than less polar compounds. Those compounds which are adsorbed more (i.e. more polar) are retained at top. Solvent is not adsorbed, so solvent runs fastest in chromatography.

Q 10 :

Methods used for purification of organic compounds are based on: [2024]

Nature of compound and presence of impurity.
Presence of impurity only.
Neither on nature of compound nor on the impurity present.
Nature of compound only.

1

2

3

4

(1)

Various methods used for the purification of organic compounds are based on the nature of the compound and the impurity present in it.

Q 11 :

On a thin layer chromatographic plate, an organic compound moved by 3.5 cm, while the solvent moved by 5 cm. The retardation factor of the organic compound is ____ $\times 10^{- 1}$ . [2024]

(7)

Retardation factor ( $R_{f}$ ) = $\frac{Distance moved by organic compound}{Distance moved by solvent}$

$= \frac{3.5}{5} = 7 \times 10^{- 1}$

Q 12 :

Using the given figure, the ratio of $R_{f}$ values of sample A and sample C is $x \times 10^{- 2}$ . Value of $x$ is ______. [2024]

(50)

$R_{f} (A) = \frac{Distance moved by A}{Distance moved by solvent} = \frac{5}{12.5}$

$R_{f} (C) = \frac{Distance moved by C}{Distance moved by solvent} = \frac{10}{12.5}$

$\frac{R_{f} (A)}{R_{f} (C)} = \frac{5 / 12.5}{10 / 12.5} = 0.5 = 50 \times 10^{- 2}$

Q 13 :

In the given TLC, the distance of spot A and B are 5 cm and 7 cm, from the bottom of TLC plate, respectively.

$R_{f}$ value of B is $x \times 10^{- 1}$ times more than A. The value of $x$ is _______. [2024]

(15)

${(R_{f})}_{B} = \frac{distance moved by B}{distance moved by solvent} = \frac{6}{8}$

$\frac{{(R_{f})}_{B}}{{(R_{f})}_{A}} = \frac{6 / 8}{4 / 8} = 15 \times 10^{- 1}$

Q 14 :

The purification method based on the following physical transformation is: [2025]

$\underset{(X)}{Solid} \overset{Heat}{\to} \underset{(X)}{Vapour} \overset{Cool}{\to} \underset{(X)}{Solid}$

Sublimation
Crystallization
Extraction
Distillation

1

2

3

4

(1)

Some solid substances change from solid to vapour state without passing through liquid state. The purification technique based on the above principle is known as sublimation and is used to separate sublimable compounds from non-sublimable impurities.

Q 15 :

Given below are two statements: [2025]

Statement I: In partition chromatography, stationary phase is thin film of liquid present in the inert support.

Statement II: In paper chromatography, the material of paper acts as a stationary phase.

In the light of the above statements, choose the correct answer from the options given below:

Statement I is true but Statement II is false
Statement I is false but Statement II is true
Both Statement I and Statement II are false
Both Statement I and Statement II are true

1

2

3

4

(1)

Partition chromatography is based on continuous differential partitioning of components of a mixture between stationary and mobile phases. Paper chromatography is a type of partition chromatography. In paper chromatography, a special quality paper known as chromatography paper is used. Chromatography paper contains water trapped in it, which acts as the stationary phase.

Q 16 :

Match List-I with List-II [2025]

List-I List-II

(Purification technique) (Mixture of organic compounds)

A. Distillation (simple) I. Diesel + Petrol

B. Fractional distillation II. Aniline + Water

C. Distillation under reduced pressure III. Chloroform + Aniline

D. Steam distillation IV. Glycerol + Spent-lye

Choose the correct answer from the options given below:

(A)-(II), (B)-(III), (C)-(IV), (D)-(I)
(A)-(II), (B)-(IV), (C)-(I), (D)-(III)
(A)-(III), (B)-(IV), (C)-(II), (D)-(I)
(A)-(III), (B)-(I), (C)-(IV), (D)-(II)

1

2

3

4

(4)

Fact based

Q 17 :

Match List-I with List-II: [2025]

List-I List-II

(Separation of) (Separation Technique)

A. Aniline from aniline-water mixture I. Simple distillation

B. Glycerol from spent-lye in soap industry II. Fractional distillation

C. Different fractions of crude oil in petroleum industry III. Distillation at reduced pressure

D. Chloroform-Aniline mixture IV. Steam distillation

Choose the correct answer from the options given below:

(A)-(IV), (B)-(III), (C)-(II), (D)-(I)
(A)-(I), (B)-(II), (C)-(III), (D)-(IV)
(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
(A)-(II), (B)-(I), (C)-(IV), (D)-(III)

1

2

3

4

(1)

Fact based

Q 18 :

Mixture of 1 g each of chlorobenzene, aniline and benzoic acid is dissolved in 50 mL ethyl acetate and placed in a separating funnel, 5 M NaOH (30 mL) was added in the same funnel. The funnel was shaken vigorously and then kept aside. The ethyl acetate layer in the funnel contains: [2025]

benzoic acid
benzoic acid and aniline
benzoic acid and chlorobenzene
chlorobenzene and aniline

1

2

3

4

(4)

Q 19 :

Match List I with List II: [2023]

List I List II

(Mixture) (Separation Technique)

A. ${CHCl}_{3} + C_{6} H_{5} {NH}_{2}$ I. Steam distillation

B. $C_{6} H_{14} + C_{5} H_{12}$ II. Differential extraction

C. $C_{6} H_{5} {NH}_{2} + H_{2} O$ III. Distillation

D. Organic compound in $H_{2} O$ IV. Fractional distillation

A – IV, B – I, C – III, D – II
A – III, B – IV, C – I, D – II
A – II, B – I, C – III, D – IV
A – III, B – I, C – IV, D – II

1

2

3

4

(2)

${CHCl}_{3} + C_{6} H_{5} {NH}_{2} ⟶ Distillation$

$C_{6} H_{14} + C_{5} H_{12} ⟶ Fractional distillation$

$C_{6} H_{5} {NH}_{2} + H_{2} O ⟶ Steam distillation$

${Organic compound in H}_{2} O ⟶ Differential extraction$

Q 20 :

Match items of column I and II. [2023]

Column I Column II

(Mixture of compounds) (Separation Technique)

A. $H_{2} O / {CH}_{2} {Cl}_{2}$ I. Crystallization

B. II. Differential solvent extraction

C. Kerosene / Naphthalene III. Column chromatography

D. $C_{6} H_{12} O_{6} / NaCl$ IV. Fractional distillation

Choose match is:

A – (iii), B – (iv), C – (ii), D – (i)
A – (i), B – (iii), C – (ii), D – (iv)
A – (ii), B – (iv), C – (i), D – (iii)
A – (ii), B – (iii), C – (iv), D – (i)

1

2

3

4

(4)

(A) ${CH}_{2} {Cl}_{2}$ and $H_{2} O$ do not mix and form two separate layers, so they can be separated by differential solvent extraction.

(B) Column chromatography.

(C) Fractional distillation, kerosene and naphthalene are different types of hydrocarbons that have different boiling points.

(D) Crystallization, $C_{6} H_{12} O_{6}$ and NaCl are different compounds with different chemical and physical properties. As a result, they can be separated from each other by crystallization.

Q 21 :

From the figure of column chromatography given below, identify incorrect statements.

A. Compound ‘c’ is more polar than ‘a’ and ‘b’

B. Compound ‘a’ is least polar

C. Compound ‘b’ comes out of the column before ‘c’ and after ‘a’

D. Compound ‘a’ spends more time in the column

Choose the correct answer from the options given below: [2023]

A, B and D only
B and D only
B, C and D only
A, B and C only

1

2

3

4

(4)

As the chromatogram, degree of polarity is a > b > c.
Statements A and B are incorrect, as ‘b’ comes out before ‘c’; the statement C is also incorrect. As ‘a’ is the most polar, so it spends most time. Hence, A, B, C are incorrect statements.

Q 22 :

Using column chromatography, mixture of two compounds ‘A’ and ‘B’ was separated. ‘A’ eluted first, this indicates ‘B’ has [2023]

low $R_{f}$ , weaker adsorption
high $R_{f}$ , stronger adsorption
high $R_{f}$ , weaker adsorption
low $R_{f}$ , stronger adsorption

1

2

3

4

(4)

Q 23 :

Thin layer chromatography of a mixture shows the following observation:

The correct order of elution in the silica gel column chromatography is [2023]

B, A, C
C, A, B
B, C, A
A, C, B

1

2

3

4

(4)

Less polar will be less adsorbed on silica gel and will rise more with eluent (mobile phase) so correct order of elution (rising) is A > C > B.

Q 24 :

Which of the following statements is correct for paper chromatography? [2023]

Paper sheet forms the stationary phase.
Water present in the pores of the paper forms the stationary phase.
Paper and water present in its pores together form the stationary phase.
Water present in the mobile phase gets absorbed by the paper which then forms the stationary phase.

1

2

3

4

(2)

Q 25 :

Following chromatogram was developed by adsorption of compound ‘A’ on a 6 cm TLC glass plate. Retardation factor of the compound ‘A’ is ______ $\times 10^{- 1}$ . [2023]

(6)

Q 26 :

Three organic compounds A, B, and C were allowed to run in thin layer chromatography using hexane and gave the following result (see figure). The $R_{f}$ value of the most polar compound is ______ $\times 10^{- 2}$ [2023]

(25)

Organic compound C is more polar

$R_{f} = \frac{distance travelled by substance}{distance travelled by solvent}$

$= \frac{2}{8} = 0.25 = 25 \times 10^{- 2}$

Q 27 :

Given below are two statements:

Statement I: Sublimation is used for the separation and purification of compounds with low melting point.

Statement II: The boiling point of a liquid increases as the external pressure is reduced.

In the light of the above statements, choose the correct answer from the options given below: [2026]

Both Statement I and Statement II are false
Statement I is false but Statement II is true
Both Statement I and Statement II are true
Statement I is true but Statement II is false

1

2

3

4

(1)

Theory based

Topic Question Set

Q 1 :

The technique used for purification of steam volatile water immiscible substances is: [2024]

Q 2 :

Chromatographic technique/s based on the principle of differential adsorption is/are
A. Column chromatography
B. Thin layer chromatography
C. Paper chromatography

Choose the most appropriate answer from the options given below: [2024]

Q 3 :

Which among the following purification methods is based on the principle of "Solubility" in two different solvents? [2024]

Q 4 :

‘Adsorption’ principle is used for which of the following purification method? [2024]

Q 7 :

The adsorbent used in adsorption chromatography is/are

A. silica gel
B. alumina
C. quick lime
D. magnesia

Choose the most appropriate answer from the options given below: [2024]

Q 9 :

The correct statements among the following, for a "chromatography" purification method is: [2024]

Q 10 :

Methods used for purification of organic compounds are based on: [2024]

Q 11 :

On a thin layer chromatographic plate, an organic compound moved by 3.5 cm, while the solvent moved by 5 cm. The retardation factor of the organic compound is ____ $\times 10^{- 1}$ . [2024]

Q 12 :

Using the given figure, the ratio of $R_{f}$ values of sample A and sample C is $x \times 10^{- 2}$ . Value of $x$ is ______. [2024]

Q 13 :

In the given TLC, the distance of spot A and B are 5 cm and 7 cm, from the bottom of TLC plate, respectively.

$R_{f}$ value of B is $x \times 10^{- 1}$ times more than A. The value of $x$ is _______. [2024]

Q 14 :

The purification method based on the following physical transformation is: [2025]

$\underset{(X)}{Solid} \overset{Heat}{\to} \underset{(X)}{Vapour} \overset{Cool}{\to} \underset{(X)}{Solid}$

Q 18 :

Mixture of 1 g each of chlorobenzene, aniline and benzoic acid is dissolved in 50 mL ethyl acetate and placed in a separating funnel, 5 M NaOH (30 mL) was added in the same funnel. The funnel was shaken vigorously and then kept aside. The ethyl acetate layer in the funnel contains: [2025]

Q 22 :

Using column chromatography, mixture of two compounds ‘A’ and ‘B’ was separated. ‘A’ eluted first, this indicates ‘B’ has [2023]

(4)

Q 23 :

Thin layer chromatography of a mixture shows the following observation:

The correct order of elution in the silica gel column chromatography is [2023]

Q 24 :

Which of the following statements is correct for paper chromatography? [2023]

(2)

Q 25 :

Following chromatogram was developed by adsorption of compound ‘A’ on a 6 cm TLC glass plate. Retardation factor of the compound ‘A’ is ______ $\times 10^{- 1}$ . [2023]

(6)

Q 26 :

Three organic compounds A, B, and C were allowed to run in thin layer chromatography using hexane and gave the following result (see figure). The $R_{f}$ value of the most polar compound is ______ $\times 10^{- 2}$ [2023]

Want Us to Email you About Special Offers & Updates?

	LIST I (Technique)		LIST II (Application)
A.	Distillation	I.	Separation of glycerol from spent-lye
B.	Fractional distillation	II.	Aniline - Water mixture
C.	Steam distillation	III.	Separation of crude oil fractions
D.	Distillation under reduced pressure	IV.	Chloroform - Aniline

	List-I		List-II
	(Purification technique)		(Mixture of organic compounds)
A.	Distillation (simple)	I.	Diesel + Petrol
B.	Fractional distillation	II.	Aniline + Water
C.	Distillation under reduced pressure	III.	Chloroform + Aniline
D.	Steam distillation	IV.	Glycerol + Spent-lye

	List-I		List-II
	(Separation of)		(Separation Technique)
A.	Aniline from aniline-water mixture	I.	Simple distillation
B.	Glycerol from spent-lye in soap industry	II.	Fractional distillation
C.	Different fractions of crude oil in petroleum industry	III.	Distillation at reduced pressure
D.	Chloroform-Aniline mixture	IV.	Steam distillation

	List I		List II
	(Mixture)		(Separation Technique)
A.	${CHCl}_{3} + C_{6} H_{5} {NH}_{2}$	I.	Steam distillation
B.	$C_{6} H_{14} + C_{5} H_{12}$	II.	Differential extraction
C.	$C_{6} H_{5} {NH}_{2} + H_{2} O$	III.	Distillation
D.	Organic compound in $H_{2} O$	IV.	Fractional distillation

	Column I		Column II
	(Mixture of compounds)		(Separation Technique)
A.	$H_{2} O / {CH}_{2} {Cl}_{2}$	I.	Crystallization
B.		II.	Differential solvent extraction
C.	Kerosene / Naphthalene	III.	Column chromatography
D.	$C_{6} H_{12} O_{6} / NaCl$	IV.	Fractional distillation

Topic Question Set

Q 1 : The technique used for purification of steam volatile water immiscible substances is: [2024]

Q 2 : Chromatographic technique/s based on the principle of differential adsorption is/are A. Column chromatography B. Thin layer chromatography C. Paper chromatography Choose the most appropriate answer from the options given below: [2024]

Q 3 : Which among the following purification methods is based on the principle of "Solubility" in two different solvents? [2024]

Q 4 : ‘Adsorption’ principle is used for which of the following purification method? [2024]

Q 7 : The adsorbent used in adsorption chromatography is/are A. silica gel B. alumina C. quick lime D. magnesia Choose the most appropriate answer from the options given below: [2024]

Q 9 : The correct statements among the following, for a "chromatography" purification method is: [2024]

Q 10 : Methods used for purification of organic compounds are based on: [2024]

Q 11 : On a thin layer chromatographic plate, an organic compound moved by 3.5 cm, while the solvent moved by 5 cm. The retardation factor of the organic compound is ____ ×10-1. [2024]

Q 12 : Using the given figure, the ratio of Rf values of sample A and sample C is x×10-2. Value of x is ______. [2024]

Q 13 : In the given TLC, the distance of spot A and B are 5 cm and 7 cm, from the bottom of TLC plate, respectively. Rf value of B is x×10-1 times more than A. The value of x is _______. [2024]

Q 14 : The purification method based on the following physical transformation is: [2025] Solid(X)→HeatVapour(X)→CoolSolid(X)

Q 18 : Mixture of 1 g each of chlorobenzene, aniline and benzoic acid is dissolved in 50 mL ethyl acetate and placed in a separating funnel, 5 M NaOH (30 mL) was added in the same funnel. The funnel was shaken vigorously and then kept aside. The ethyl acetate layer in the funnel contains: [2025]

Q 19 : Match List I with List II: [2023] List I List II (Mixture) (Separation Technique) A. CHCl3+C6H5NH2 I. Steam distillation B. C6H14+C5H12 II. Differential extraction C. C6H5NH2+H2O III. Distillation D. Organic compound in H2O IV. Fractional distillation

Q 20 : Match items of column I and II. [2023] Column I Column II (Mixture of compounds) (Separation Technique) A. H2O/CH2Cl2 I. Crystallization B. II. Differential solvent extraction C. Kerosene / Naphthalene III. Column chromatography D. C6H12O6/NaCl IV. Fractional distillation Choose match is:

Q 22 : Using column chromatography, mixture of two compounds ‘A’ and ‘B’ was separated. ‘A’ eluted first, this indicates ‘B’ has [2023]

(4)

Q 23 : Thin layer chromatography of a mixture shows the following observation: The correct order of elution in the silica gel column chromatography is [2023]

Q 24 : Which of the following statements is correct for paper chromatography? [2023]

(2)

Q 25 : Following chromatogram was developed by adsorption of compound ‘A’ on a 6 cm TLC glass plate. Retardation factor of the compound ‘A’ is ______ ×10-1. [2023]

(6)

Q 26 : Three organic compounds A, B, and C were allowed to run in thin layer chromatography using hexane and gave the following result (see figure). The Rf value of the most polar compound is ______ ×10-2 [2023]

Want Us to Email you About Special Offers & Updates?

Q 1 :

The technique used for purification of steam volatile water immiscible substances is: [2024]

Q 2 :

Chromatographic technique/s based on the principle of differential adsorption is/are
A. Column chromatography
B. Thin layer chromatography
C. Paper chromatography

Choose the most appropriate answer from the options given below: [2024]

Q 3 :

Which among the following purification methods is based on the principle of "Solubility" in two different solvents? [2024]

Q 4 :

‘Adsorption’ principle is used for which of the following purification method? [2024]

Q 7 :

The adsorbent used in adsorption chromatography is/are

A. silica gel
B. alumina
C. quick lime
D. magnesia

Choose the most appropriate answer from the options given below: [2024]

Q 9 :

The correct statements among the following, for a "chromatography" purification method is: [2024]

Q 10 :

Methods used for purification of organic compounds are based on: [2024]

Q 11 :

On a thin layer chromatographic plate, an organic compound moved by 3.5 cm, while the solvent moved by 5 cm. The retardation factor of the organic compound is ____ $\times 10^{- 1}$ . [2024]

Q 12 :

Using the given figure, the ratio of $R_{f}$ values of sample A and sample C is $x \times 10^{- 2}$ . Value of $x$ is ______. [2024]

Q 13 :

In the given TLC, the distance of spot A and B are 5 cm and 7 cm, from the bottom of TLC plate, respectively.

$R_{f}$ value of B is $x \times 10^{- 1}$ times more than A. The value of $x$ is _______. [2024]

Q 14 :

The purification method based on the following physical transformation is: [2025]

$\underset{(X)}{Solid} \overset{Heat}{\to} \underset{(X)}{Vapour} \overset{Cool}{\to} \underset{(X)}{Solid}$

Q 18 :

Mixture of 1 g each of chlorobenzene, aniline and benzoic acid is dissolved in 50 mL ethyl acetate and placed in a separating funnel, 5 M NaOH (30 mL) was added in the same funnel. The funnel was shaken vigorously and then kept aside. The ethyl acetate layer in the funnel contains: [2025]

Q 22 :

Using column chromatography, mixture of two compounds ‘A’ and ‘B’ was separated. ‘A’ eluted first, this indicates ‘B’ has [2023]

Q 23 :

Thin layer chromatography of a mixture shows the following observation:

The correct order of elution in the silica gel column chromatography is [2023]

Q 24 :

Which of the following statements is correct for paper chromatography? [2023]

Q 25 :

Following chromatogram was developed by adsorption of compound ‘A’ on a 6 cm TLC glass plate. Retardation factor of the compound ‘A’ is ______ $\times 10^{- 1}$ . [2023]

Q 26 :

Three organic compounds A, B, and C were allowed to run in thin layer chromatography using hexane and gave the following result (see figure). The $R_{f}$ value of the most polar compound is ______ $\times 10^{- 2}$ [2023]