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

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]

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(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]

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(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]

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(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

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(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

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(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)

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(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)

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(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

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(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

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(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)

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(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.

Topic Question Set

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]

0%

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]

0%

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]

0%

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]

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	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