Chemistry · 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 chemistry world energy needs coal petroleum non-renewable sources of energy

________ is a process by which components in a chemical mixture are separated into different parts according to different boiling points in a fractionating column.

  1. Vacuum distillation

  2. Steam distillation

  3. Fractional distillation

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Vacuum distillation is a distillation of a liquid under reduced pressure, enabling it to boil at a lower temperature than normal.

Steam distillation of a liquid in a current of steam used especially to purify liquids that are not very volatile and are immiscible with water.

Fractional distillation is a separation of a liquid mixture into fractions differing in boiling point (and hence chemical composition) by means of distillation, typically using a fractionating column.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

Petroleum refining involves:

  1. vacuum distillation

  2. steam distillation

  3. fractional distillation

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

The various fractions of petroleum are separated by fractional distillation.
Fractional distillation is one separation of a mixture into its components parts, or fractions, sour as in separating chemical compounds by their boiling point by heating them to a temp at which one or more fractions of the compound will vaporize.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

The process of crystallization is used to obtain pure solids because:

  1. iIt is better than evaporation

  2. impurities are filtered completely

  3. ultra pure crystals are formed

  4. decomposition does not take place
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Since crystallization generally produces salts which are crystalline in state or $100$ percent purity in state.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

What is the method to separate two compounds with different solubilities in a solvent? 

  1. Sublimation

  2. Crystallization

  3. Chromatography

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

Two compounds which have different solubilities in a solvent S can be separated from each other by Fractional Crystallisation. The process involves a series of repeated-crystallisations. The mixture of the two compounds in the solvent S is heated so as to make it saturated. When the hot solution is allowed to cool, the less soluble substance crsytallises out first while the more soluble substance remains in the solution. The crystals of first compound are separated from the mother liquor and the mother liquor is again concentrated and allowed to cool when the crystals of the 2nd compound are obtained.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

Separation of a mixture into its components, whose boiling points are different, is called :

  1. fractional distillation

  2. destructive distillation

  3. displacement

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

Separation of a mixture into its components whose boiling points are different is called Fractional distillation.
This method is used for separating a mixture of two or more volatile liquids both having close boiling points. The boiling points of two components differ by 10-15 K. For example, acetone and methanol with boiling points 329 K and 338 K can be separated  by this method. This method is used for distillation of petroleum, coal tar and crude alcohol.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

Which of the following is/are true?

  1. When carbolic oil is cooled, naphthalene crystallizes out

  2. Naphthalene is purified by sublimation

  3. Naphthalene is used for manufacture of dyes, drugs, explosives etc

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All of the following statements are true.
When carbolic oil is cooled, naphthalene crystallizes out.
Naphthalene is purified by sublimation.
Naphthalene is used for manufacture of dyes, drugs, explosives etc.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

Separation of two substances by crystallisation depends upon their differences in:

  1. densities

  2. solublity

  3. melting point

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

Separation of $2$ substances by crystallization depends upon their difference in solubility as more soluble impurity will go into the solution and less soluble component will crystallize out.

Multiple choice bio-chemistry cell structure membrane bound organelles cell: size and differentiation microscopy

Which of the following statements is false?

  1. Electrophoresis can help separate proteins.

  2. Image formed by compound microscope is vertical and erect.

  3. An angstrom is one-hundredth of a micron.

  4. Unstained living cells can be studied with the help of a phase-contrast microscope.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An angstrom is 10^-10 meters, while a micron is 10^-6 meters. Therefore, an angstrom is 10^-4 of a micron, not one-hundredth. The other statements are standard biological/microscopy facts.

Multiple choice chemistry composition of matter heterogeneous mixture - suspension and its properties suspension types of mixture

Suspension is a heterogeneous mixture in which very fine particles of a solid are dispersed in any medium (liquid or gas). Fine particles of the solid remain suspended in the medium.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A suspension is a heterogeneous mixture in which very fine particles of a solid are dispersed in any medium (liquid or gas). Fine particles of the solid remain suspended in the medium.

Following are the characteristics properties of suspensions

i) Heterogeneous nature: a suspension is a heterogeneous system.

ii) Visibility: the particles in a suspension can be seen with naked eyes or under a simple microscope.

iii) Particle Size: in a suspension, the size of the particles is of the order of 10-7 make or larger.

iv) Sedimentation: the particles in a suspension travel tendency to settle down. Very fine particles, however, remain suspended in the medium.

v) Separation by filtration: Larger particles in a suspension can be separated from the liquid or air by the filtration. 

Multiple choice chemistry composition of matter heterogeneous mixture - suspension and its properties suspension types of mixture

Powder coating is a process which requires a solvent to keep the binder and filler parts in a liquid suspension form.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form while liquid paints require.