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

   

Q 22 :

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

• low ${\mathrm{R}}_{\mathrm{f}}$, weaker adsorption

   

• high ${\mathrm{R}}_{\mathrm{f}}$, stronger adsorption

   

• high ${\mathrm{R}}_{\mathrm{f}}$, weaker adsorption

   

• low ${\mathrm{R}}_{\mathrm{f}}$, stronger adsorption

   

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

   

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.

   

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]

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