Chromatography: A Comprehensive Guide to Separating Mixtures

Question 1

In gas chromatography, compounds are separated based on their:

Accepted Answer

Volatility

Answer

Polarity

Answer

Size

Answer

Charge

Question 2

What is the purpose of a mobile phase in chromatography?

Accepted Answer

To carry the sample through the stationary phase

Answer

To dissolve the sample

Answer

To separate the compounds in the sample

Answer

To detect the separated compounds

Question 3

Which factor does NOT affect the separation of compounds in chromatography?

Accepted Answer

Detector sensitivity

Answer

Temperature

Answer

pH

Answer

Sample size

Question 4

In adsorption chromatography, the separation of compounds is based on their:

Accepted Answer

Affinity for the stationary phase

Answer

Solubility in the mobile phase

Answer

Boiling point

Answer

Molecular weight

Question 5

In ion exchange chromatography, the stationary phase contains:

Accepted Answer

Both positively and negatively charged groups

Answer

Positively charged groups

Answer

Negatively charged groups

Answer

Neutral groups

Question 6

Which of the following is NOT a type of chromatography mentioned in this unit?

Accepted Answer

Centrifugation

Answer

Paper chromatography

Answer

Thin-layer chromatography

Answer

Gas chromatography

Question 7

In paper chromatography, what acts as the stationary phase?

Accepted Answer

The paper itself

Answer

The solvent

Answer

The sample

Answer

The adsorbent

Question 8

When choosing a solvent for chromatography, which factor is the most crucial to consider?

Accepted Answer

The polarity of the solvent

Answer

The boiling point of the solvent

Answer

The cost of the solvent

Answer

The availability of the solvent

Question 9

In gas chromatography, how are volatile compounds analyzed?

Accepted Answer

Using a stationary liquid phase and a mobile gas phase to separate substances based on their volatility.

Answer

Using a solid stationary phase and a liquid mobile phase to separate substances based on their polarity.

Answer

Using a gas as both the stationary and mobile phases to separate substances based on their boiling points.

Question 10

In the field of environmental analysis, which of the following is NOT a common application of chromatography?

Accepted Answer

Determining the age of fossils

Answer

Detecting pesticides in water samples

Answer

Identifying heavy metals in soil samples

Answer

Analyzing the composition of air pollutants

Question 11

Explain how the properties of the stationary and mobile phases affect the effectiveness of chromatographic separation.

Accepted Answer

The characteristics of both the stationary and mobile phases significantly impact separation efficiency.

Answer

Strong stationary and weak mobile phases enhance separation efficiency.

Answer

Weak stationary and strong mobile phases contribute to improved separation.

Answer

The stationary phase primarily governs separation, with the mobile phase having a limited influence.

Question 12

Which option is NOT a recognized type of chromatography?

Accepted Answer

Capillary electrophoresis

Answer

Paper chromatography

Answer

Thin-layer chromatography

Answer

High-performance liquid chromatography

Question 13

What is the primary function of the stationary phase in chromatography?

Accepted Answer

Provides a surface for sample interaction

Answer

Acts as the mobile phase

Answer

Separates the components of the mixture

Answer

Prevents sample movement

Question 14

Explain the process of thin-layer chromatography.

Accepted Answer

A thin layer of adsorbent is spread on a plate, the sample is applied, and a solvent moves up the plate by capillary action.

Answer

An adsorbent is packed into a column, the sample is introduced, and a solvent passes through the column.

Answer

The sample and a solvent are heated, and components are separated based on boiling points.

Answer

The sample and a solvent are centrifuged, and components are separated based on density.

Question 15

How is chromatography useful for identifying an unknown compound?

Accepted Answer

Comparing the Rf value of the unknown to known compounds

Answer

Comparing the color of the unknown to known compounds

Answer

Comparing the smell of the unknown to known compounds

Answer

Comparing the boiling point of the unknown to known compounds

Question 16

Which chromatography technique is optimal for separating a complex mixture of volatile organic compounds with low boiling points?

Accepted Answer

Gas Chromatography

Answer

Paper Chromatography

Answer

Thin-Layer Chromatography

Answer

Liquid Chromatography

Question 17

How does chromatography contribute to environmental analysis?

Accepted Answer

Identifies the types of pollutants in environmental samples.

Accepted Answer

Determines the concentrations of pollutants in environmental samples.

Answer

Assesses the toxicity of pollutants in environmental samples.

Answer

Is not applicable for analyzing environmental samples.

Question 18

In paper chromatography, which component serves as the stationary phase?

Accepted Answer

The paper itself

Answer

The solvent used

Answer

The sample being separated

Answer

The developing agent employed

Question 19

Which chromatography technique is specifically designed to separate ions based on their electrical charge?

Accepted Answer

Ion-exchange chromatography

Answer

Paper chromatography

Answer

Thin-layer chromatography

Answer

Gas chromatography

Question 20

The Rf value in chromatography represents:

Accepted Answer

The ratio of the sample's distance to the solvent's distance

Answer

The distance traveled by the solvent

Answer

The distance traveled by the sample

Answer

The concentration of the sample

Question 21

Compared to paper chromatography, a key advantage of thin-layer chromatography lies in:

Accepted Answer

Improved resolution

Answer

Faster separation

Answer

Lower cost

Answer

Greater sensitivity

Question 22

In gas chromatography, the sample is typically converted into a gas prior to analysis.

Accepted Answer

True

Answer

False

Question 23

Chromatography is an analytical technique that permanently alters the sample being analyzed.

Accepted Answer

False

Answer

True

Question 24

Which of the following is NOT a type of chromatography technique?

Accepted Answer

Titration

Answer

Paper chromatography

Answer

Thin-layer chromatography

Answer

Gas chromatography

Question 25

What is the fundamental principle behind thin-layer chromatography (TLC)?

Accepted Answer

Adsorption of the sample onto a solid support

Answer

Partitioning of the sample between two immiscible liquids

Answer

Gel filtration of the sample through a porous matrix

Answer

Electrophoresis of the sample through a gel

Question 26

What does the Rf value represent in chromatography?

Accepted Answer

The ratio of the distance traveled by the sample to the distance traveled by the solvent

Answer

The concentration of the sample

Answer

The polarity of the sample

Answer

The molecular weight of the sample

Question 27

What is the primary function of the mobile phase in chromatography?

Accepted Answer

To carry the sample through the stationary phase

Answer

To dissolve the stationary phase

Answer

To separate the components of the sample

Answer

To visualize the separated components

Question 28

Which of the following is NOT a fundamental principle of chromatography?

Accepted Answer

Substances with different chemical properties travel at the same rate.

Answer

The stationary phase is immobile.

Answer

The mobile phase moves through the stationary phase.

Question 29

Which type of chromatography is used to separate particles based on their size and shape?

Accepted Answer

Gel filtration chromatography

Answer

Paper chromatography

Answer

Gas chromatography

Answer

Thin-layer chromatography

Question 30

In paper chromatography, the stationary phase is composed of:

Accepted Answer

Paper

Answer

Aluminum oxide

Answer

Silica gel

Answer

Activated carbon

Question 31

The Rf value of a substance is defined as:

Accepted Answer

The distance traveled by the substance relative to the distance traveled by the solvent front.

Answer

The ratio of the speed of the substance to the speed of the solvent front.

Answer

The distance traveled by the solvent front relative to the distance traveled by the substance.

Question 32

Which of the following applications of chromatography involves quantifying the concentration of a substance?

Accepted Answer

Determining the purity of a compound.

Answer

Analyzing the composition of food

Answer

Separating proteins in a cell lysate

Answer

Identifying drugs in urine

Question 33

In gas chromatography, the stationary phase is typically:

Accepted Answer

A liquid coated on an inert solid support.

Answer

A gas

Answer

A packed solid

Answer

A liquid

Question 34

The most common technique used to identify substances separated by chromatography is:

Accepted Answer

Spectroscopy

Answer

Electrophoresis

Answer

Microscopy

Answer

Titration

Question 35

Which of the following is a key advantage of high-performance liquid chromatography (HPLC) over other chromatographic techniques?

Accepted Answer

Higher resolution and sensitivity

Answer

Faster analysis time

Answer

Lower cost

Question 36

Which of the following is NOT a type of chromatography?

Accepted Answer

Centrifugation

Answer

Paper chromatography

Answer

Gas chromatography

Answer

Liquid chromatography

Question 37

In paper chromatography, what acts as the stationary phase?

Accepted Answer

Paper

Answer

Detector

Answer

Solvent

Answer

Sample

Question 38

What is the primary function of a detector in chromatography?

Accepted Answer

To identify and measure the separated components

Answer

To visualize the separated components

Answer

To prepare the sample

Answer

To separate the components

Question 39

In forensic science, which application of chromatography is commonly used?

Accepted Answer

Identifying drugs in blood

Answer

Separating pigments in plants

Answer

Analyzing food additives

Question 40

What is the key difference between elution and adsorption chromatography?

Accepted Answer

Elution involves passing a mobile phase through a stationary phase, while adsorption involves the binding of a sample to a stationary phase.

Answer

Elution is used to separate polar compounds, while adsorption is used to separate nonpolar compounds.

Question 41

Which characteristic is desirable in a chromatographic column?

Accepted Answer

High efficiency and low pressure drop

Answer

High efficiency and high pressure drop

Answer

Low efficiency and low pressure drop

Answer

Low efficiency and high pressure drop

Question 42

What is the primary role of the mobile phase in chromatography?

Accepted Answer

To carry the sample through the stationary phase

Answer

To detect the separated components

Answer

To prepare the sample for chromatography

Answer

To separate the components of the sample

Question 43

What is the fundamental principle behind the separation of components in chromatography?

Accepted Answer

Differential migration of components based on their interactions with the stationary and mobile phases

Answer

Electrical attraction between components

Question 44

In paper chromatography, what acts as the stationary phase?

Accepted Answer

Paper

Answer

Water

Answer

Glass

Answer

Sand

Question 45

Which is the purpose of the developing solvent in chromatography?

Accepted Answer

To carry the sample components through the stationary phase

Answer

To dissolve the sample

Answer

To stop the separation process

Answer

To react with the sample

Question 46

What is the underlying mechanism of thin-layer chromatography?

Accepted Answer

Differential adsorption of sample components onto a solid surface

Answer

Differential solubility of sample components in a liquid

Answer

Differential volatility of sample components

Question 47

What does the Rf value represent in chromatography?

Accepted Answer

The ratio of the distance travelled by the sample component to the distance travelled by the solvent

Answer

The amount of sample present

Answer

The polarity of the sample

Question 48

Which is a limitation of the chromatography technique?

Accepted Answer

It cannot separate large molecules

Answer

It can separate any type of mixture

Answer

It is inexpensive

Answer

It is not time-consuming

Question 49

What is the distinction between preparative and analytical chromatography?

Accepted Answer

Preparative chromatography is for purifying substances, while analytical chromatography is for identifying and quantifying substances.

Answer

Preparative chromatography is faster than analytical chromatography.

Question 50

Which of the following represents a recent advancement in chromatography?

Accepted Answer

High-performance liquid chromatography (HPLC)

Answer

Paper chromatography

Answer

Gas chromatography

Answer

Thin-layer chromatography