Chemistry ยท Science General

Separation Techniques

842 Questions

Separation techniques involve physical methods to isolate mixtures, including distillation, filtration, and crystallization. Competitive exams frequently test these foundational concepts. Review the exact processes to enhance problem solving speed.

Distillation and evaporationCrystallization processFiltration methodsSeparating dissolved solidsChromatography and mass techniques

Separation Techniques Questions

Multiple choice

Which of the following is NOT a common type of downstream processing operation used in bioprocessing?

  1. Filtration

  2. Centrifugation

  3. Chromatography

  4. Crystallization

  5. Drying
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Drying is not a common type of downstream processing operation used in bioprocessing, as it is typically used for the production of solid products, which are not common in bioprocessing.

Multiple choice

Which of the following is not a commonly used unit operation in downstream processing?

  1. Filtration

  2. Centrifugation

  3. Chromatography

  4. Crystallization
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Crystallization is not typically used in downstream processing, as it is primarily employed for the purification of solid compounds, whereas downstream processing focuses on the separation and purification of biomolecules.

Multiple choice

Which type of chromatography is commonly used for the separation of proteins based on their size?

  1. Size-exclusion chromatography

  2. Ion-exchange chromatography

  3. Affinity chromatography

  4. Reversed-phase chromatography
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Size-exclusion chromatography (SEC) is widely used for the separation of proteins based on their size, as it allows molecules of different sizes to elute from the column at different times.

Multiple choice

What is the principle behind ion-exchange chromatography?

  1. Separation of molecules based on their charge.

  2. Separation of molecules based on their size.

  3. Separation of molecules based on their hydrophobicity.

  4. Separation of molecules based on their affinity for a specific ligand.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ion-exchange chromatography separates molecules based on their charge, as positively charged molecules bind to negatively charged resins, while negatively charged molecules bind to positively charged resins.

Multiple choice

Which of the following is not a common method for the purification of nucleic acids?

  1. Phenol-chloroform extraction

  2. Ethanol precipitation

  3. Ion-exchange chromatography

  4. Size-exclusion chromatography
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Size-exclusion chromatography is not commonly used for the purification of nucleic acids, as it separates molecules based on their size, which is not a primary factor in nucleic acid purification.

Multiple choice

Which of the following is not a common method for the purification of enzymes?

  1. Affinity chromatography

  2. Ion-exchange chromatography

  3. Size-exclusion chromatography

  4. Reversed-phase chromatography
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Reversed-phase chromatography is not commonly used for the purification of enzymes, as it is primarily employed for the separation of small hydrophobic molecules, whereas enzymes are typically large and hydrophilic.

Multiple choice

Which of the following is not a common method for the purification of lipids?

  1. Thin-layer chromatography

  2. Gas chromatography

  3. High-performance liquid chromatography

  4. Size-exclusion chromatography
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Size-exclusion chromatography is not commonly used for the purification of lipids, as it separates molecules based on their size, which is not a primary factor in lipid purification.

Multiple choice

What is the primary principle behind the separation of compounds in chromatography?

  1. Differential solubility

  2. Differential volatility

  3. Differential adsorption

  4. Differential ionization
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In chromatography, compounds are separated based on their differential adsorption to a stationary phase, which can be a solid or a liquid.

Multiple choice

Which of the following is not a type of chromatography:

  1. Gas chromatography

  2. Liquid chromatography

  3. Thin-layer chromatography

  4. Electrophoresis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electrophoresis is not a type of chromatography as it separates molecules based on their charge and size, rather than their differential adsorption.

Multiple choice

In gas chromatography, the mobile phase is:

  1. A liquid

  2. A solid

  3. A gas

  4. A supercritical fluid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In gas chromatography, the mobile phase is a carrier gas, typically helium or nitrogen, which carries the sample through the column.

Multiple choice

The stationary phase in liquid chromatography is typically:

  1. A solid

  2. A liquid

  3. A gas

  4. A supercritical fluid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In liquid chromatography, the stationary phase is a solid matrix, such as silica gel or alumina, which adsorbs the sample components.

Multiple choice

The separation of compounds in thin-layer chromatography is based on:

  1. Differential solubility

  2. Differential volatility

  3. Differential adsorption

  4. Differential ionization
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In thin-layer chromatography, compounds are separated based on their differential adsorption to a stationary phase, which is a thin layer of adsorbent material coated on a glass or plastic plate.

Multiple choice

Which of the following is not a factor that affects the resolution of a chromatographic separation:

  1. Column length

  2. Particle size of the stationary phase

  3. Flow rate of the mobile phase

  4. Temperature of the column
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Temperature typically does not have a significant effect on the resolution of a chromatographic separation.

Multiple choice

Which of the following is not a type of purification technique:

  1. Crystallization

  2. Distillation

  3. Chromatography

  4. Extraction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chromatography is a separation technique, not a purification technique.

Multiple choice

The process of removing impurities from a substance by dissolving it in a solvent and then filtering it is known as:

  1. Crystallization

  2. Distillation

  3. Extraction

  4. Filtration
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Filtration is a purification technique that involves removing impurities from a substance by dissolving it in a solvent and then filtering it.