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 correct sequence of the processes involved in separating impure common salt (containing sand and dirt) that is dissolved in water?

  1. Filtration - Sedimentation - Decantation - Evaporation

  2. Sedimentation - Evaporation - Filtration - Decantation

  3. Decantation - Sedimentation - Filtration - Evaporation

  4. Filtration - Decantation - Sedimentation - Evaporation

  5. Sedimentation - Decantation - Filtration - Evaporation
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option.  

Multiple choice

Which of the following statements is/are false?

a. Separation by sieving is possible only if the size of one kind of particles is bigger and the size of other kind of particles is smaller than the size of holes in the sieve. b. Residue is the clear liquid obtained after filtration. c. Wheat flour and chaff can be removed by using the method of sieving.

  1. Only a

  2. Both a and b

  3. Only b

  4. Both b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct option as this statement is false.  

Multiple choice

The process of distillation is used to separate two miscible liquids. The technique of distillation is based on the _________ of components of mixture.

  1. difference in freezing points

  2. fractional difference in their boiling points

  3. travel speed of components

  4. difference in the boiling points

  5. difference in weights
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, the liquid which boils at lower temperature is vapourised at lower temperature. The technique of distillation is based on the difference in boiling points of components of mixture.

Multiple choice

In which of the following applications is separation of components not done, on the basis of fractional differences in the boiling points of components?

  1. In petroleum refineries, petrochemical and chemical plants

  2. In separation of fat from milk

  3. In oil refineries to separate crude oil into useful substances

  4. In the separation of ethanol and water

  5. In the separation of oxygen, liquid nitrogen and argon from air
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, it is the correct answer as fat from milk is separated by centrifugation method.

Multiple choice

By the method of centrifugation, which type of components are separated in a mixture of two immiscible liquids?

  1. Components which are chemically different

  2. Components which are heavier and lighter

  3. Components which are of different colours

  4. Components that have a fractional difference in their boiling points

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the method of centrifugation, the centripetal and centrifugal forces are used to separate lighter and heavier components of the mixture of two immiscible liquids.

Multiple choice

An important step in the manufacture of pulp for paper industry from the woody tissues of plants is the

  1. removal of water from the wood by prolonged heating at approximately 50oC.

  2. treatment of wood with chemical that breaks down cellulose.

  3. removal of oils present in the wood by treatment with suitable chemicals.

  4. preparation of pure cellulose by removing lignin.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 An important step in the manufacture of pulp for paper industry from the woody tissues of plants is the preparation of pure cellulose by removing lignin.

Multiple choice

By which method can you separate a mixture of NaCl and water?

  1. Sublimation

  2. Distillation

  3. Solvent extraction

  4. Liquefaction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Distillation is the correct method because NaCl (salt) has a much higher boiling point than water, so when the solution is heated, water evaporates first and can be collected as distillate, leaving solid salt behind. Sublimation is for solids that directly vaporize, solvent extraction requires another solvent, and liquefaction is converting gas to liquid - none of these separate salt from water effectively.

Multiple choice

Filtration is used to separate _______ from a liquid.

  1. gases

  2. liquid

  3. solid

  4. all of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Filtration specifically separates undissolved solid particles from a liquid - the filter paper allows the liquid to pass through while trapping solid particles. Gases pass through filters, liquids mix with liquids, and 'all of these' would be incorrect because filtration cannot separate gases or miscible liquids.

Multiple choice

The process of evaporation is used to separate

  1. cream from milk

  2. sugar from water

  3. alcohol from water

  4. sand from water
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Evaporation separates sugar from water because when you heat a sugar solution, water (with lower boiling point) evaporates into the air, leaving solid sugar crystals behind. This works because sugar is non-volatile and has a much higher boiling point than water. Cream separation uses centrifugation or churning, alcohol-water separation requires distillation due to closer boiling points, and sand-water would use filtration or sedimentation.