2nd Year Chemistry Chapter 12 TestCHROMATOGRAPHY

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

1. Chromatography can be used to separate:

   1. Only coloured substances

   2. Only colourless substances

   3. Both coloured and colourless substances

   4. Neither coloured nor colourless substances

2. The topmost wet line reached by the solvent on the chromatography paper is called the:

   1. Base line

   2. Starting point

   3. Solvent front

   4. Retardation line

3. Why is activated charcoal used in filters and purification systems?

   1. Because it dissolves impurities

   2. Because it filters by size only

   3. Because it adsorbs gases and impurities onto its surface

   4. Because it reacts chemically to destroy pollutants

4. Chromatography separates components of a mixture based on their varying affinities for:

   1. Two different phases

   2. Two identical states

   3. Temperature changes

   4. Gravitational forces

5. A substance has a very low R, value. What does this indicate?

   1. It is insoluble in the solvent

   2. It is highly soluble in the solvent

   3. It strongly sticks to the water inside paper

   4. It has a high density

6. Apolar compound in TLC will usually:

   1. Travel farther up the plate

   2. Stay near the baseline

   3. Evaporate quickly

   4. Dissolve completely

7. What is the role of the carrier gas in gas chromatography?

   1. To react with the sample

   2. To act as stationary phase

   3. To carry vapourised sample through the column

   4. To detect the substances

8. Chromatography allows for which of the following operations?

   1. Identification

   2. Purification

   3. Quantification

   4. All of the above

9. Why do some components of a dye travel further up the paper than others?

   1. They are more soluble in the water trap in paper (stationary phase)

   2. They are more soluble in the solvent (mobile phase)

   3. They react with the paper

   4. They have higher density

10. What is the unit of the Retardation factor R_f?

    1. Centimeters (cm)

    2. Millimeters (mm)

    3. No unit

    4. Percent (%)