Chemistry · Science General

Separation Techniques

813 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 the criteria to use chromatography for separating components of a mixture?

  1. This method used to separate a mixture comprising of solutes that dissolve in the same solvent.

  2. This method is used for the separation of a mixture containing two miscible liquids that boil without decomposing and have a large difference between their boiling points.

  3. Two immiscible liquids are separated by this method.

  4. In case the difference in the boiling points of the liquids is less than 25 kelvin temperature, we use the chromatography method.

  5. This method is used as a separation and purification method that involves the precipitating of solid crystals from its saturated solution on cooling.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct answer. Chromatography is a method used to separate a mixture comprising of solutes that dissolve in the same solvent. Chromatography is used for separating colours in a dye, pigments from natural colours and drugs from blood.

Multiple choice

Which of the following substances represents the trademark for adsorbent used in the column chromatography of lipids?

  1. Cetavlon

  2. Clinistix

  3. Dowex

  4. Duponol

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

Column chromatography is the method used in purification of individual chemical compounds from a mixture of compounds where the stationary phase is placed in a vertical glass column. Florisil refers to the trademark for a magnesium silicate adsorbent used in the column chromatography of lipids.

Multiple choice

Chromatography is based on the principle of

  1. difference in density

  2. difference in absorption

  3. difference in mass

  4. difference in adsorption
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chromatography is based on the principle of difference in adsorption.

Multiple choice

Which of the following techniques of chromatography is performed on a sheet of glass, plastic, or aluminum foil?

  1. Column chromatography

  2. Planar chromatography

  3. Paper chromatography

  4. Thin layer chromatography
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Thin layer chromatography (TLC) is a chromatography technique used to separate mixtures. Thin layer chromatography is performed on a sheet of glass, plastic, or aluminum foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide, or cellulose (blotter paper).

Multiple choice

Chromatography may be preparative or analytical. In which of the following chromatographic techniques, both the stationary and mobile phases are liquids?

  1. Reversed-phase chromatography

  2. Pyrolysis gas chromatography

  3. Fast protein liquid chromatography

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

Countercurrent chromatography (CCC) is a type of liquid-liquid chromatography, where both the stationary and mobile phases are liquids. The operating principle of CCC equipment requires a column consisting of an open tube coiled around a bobbin.

Multiple choice

The chromatography technique used for the separation of stereoisomers is

  1. ion exchange chromatography

  2. size-exclusion chromatography

  3. reversed-phase chromatography

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

Chiral chromatography involves the separation of stereoisomers.To enable chiral separation to take place, either the mobile phase or the stationary phase must be made chiral, giving differing affinities between the analytes.

Multiple choice

The aim of chromatography is to separate the components of a mixture. Which of the following chromatography processes is always carried out in a column?

  1. Gas chromatography

  2. Liquid chromatography

  3. Affinity chromatography

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

Gas chromatography (GC), also known as Gas-Liquid chromatography, (GLC), is a separation technique in which the mobile phase is a gas. Gas chromatography is always carried out in a column which is typically packed or capillary.

Multiple choice

Which of the following statements is/are true? A. In column chromatography, the more highly absorbed component is eluted with less polar solvents. B. Benzoic acid can be extracted from water using ethanol. C. Number of replaceable hydroxyl ions present in one molecule of a base is called its acidity.

  1. Only A

  2. Only B

  3. Only C

  4. A and B

  5. B and C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because number of replaceable hydroxyl ions present in one molecule of a base is called its acidity is true statement.

Multiple choice

The highest probability of obtaining a pure culture lies in

  1. pour plate method

  2. spread plate method

  3. streak plate method

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

The most probable method of obtaining a pure culture is by streak plate method. Individual colonies can be obtained in the fourth quadrant.

Multiple choice

Directions: The first and the last sentences of the passage are numbered 1 and 6, respectively. The rest of the passage is split into four parts named A, B, C and D. These four parts are not given in their proper order. Read the sentences and find out which of the following combinations is correct.

  1. Chromatography is used to separate mixtures of substances into their components. A. Different components travel at different rates. B. The mobile phase flows through the stationary phase and carries the components of the mixture with it. C. They all have a stationary phase (a solid or a liquid supported on a solid) and a mobile phase (a liquid or a gas). D. All forms of chromatography work on the same principle.
  2. In paper chromatography, the stationary phase is a very uniform absorbent paper, while the mobile phase is a suitable liquid solvent or mixture of solvents.

  1. CADB

  2. DCBA

  3. DBCA

  4. ADBC

  5. CDBA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

“They all have” in C refers to “the same principle” in D, so C follows D. B provides an explanation of the components mentioned in C (general to specific), so B follows C. Hence, the answer is DCBA.

Multiple choice

Ethyl alcohol is mixed completely with water. How ethyl alcohol is separated from the mixture?

  1. By separation flannel

  2. By evaporation

  3. Partial distillation

  4. Evaporation of water
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fractional distillation (partial distillation) separates miscible liquids with different boiling points. Ethanol boils at 78°C while water boils at 100°C, so repeated vaporization-condensation cycles can enrich the ethanol content. Simple evaporation wouldn't work as both components would evaporate, and 'separation flannel' is not a standard separation technique.