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 bio-chemistry biochemical techniques methods of purification of organic compounds methods of purification - organic compounds chromatography

Osazone formation is used to separate and identify.

  1. Alcohols

  2. Carboxylic acids

  3. Carbohydrates

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

Osazones are characteristic crystalline derivatives formed by the reaction of reducing sugars (carbohydrates) with phenylhydrazine. They are used to identify specific sugars.

Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

Turpentine oil can be purified by:

  1. steam distillation

  2. vaccum distillation

  3. fractional distillation

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

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. The boiling point of turpentine oil is between 90 and 115 °C or 195 and 240 °F and is immiscible with water. Thus, it is purified by steam distillation.

Multiple choice bio-chemistry biochemical techniques methods of purification of organic compounds methods of purification - organic compounds chromatography

A mixture of camphor and benzoic acid can be easily separated by?

  1. Sublimation

  2. Fractional distillation

  3. Chemical method

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

Aqueous solution of $NaHCO _3$ can be used to separate benzoic acid from its mixture with camphor. Benzoic acid forms water soluble sodium benzoate with $NaHCO _3$. So, A mixture of camphor and benzoic acid can be easily separated by Chemical method.

Option C is correct.

Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

A substance which decomposes at or below its boiling point cannot be purified by?

  1. Steam distillation

  2. Simple distillation

  3. Fractional distillation

  4. Distillation under reduced pressure
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

Steam distillation is used for natural aromatic compounds which are immiscible in water.
Simple and fractional distillation uses the property of difference in the boiling point. These techniques can not be used for the substance which decomposes at or below its boiling point.
Distillation under reduced pressure is basically Vaccum distillation. This method is used to boil such substances without their decomposition

Option A, B and C are the answer.
Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

The fragrance of the flower is due to the presence of some steam volatile organic compounds called essential oils. These are generally insoluble in water at room temperature but are miscible with water vapour in the vapour phase. A suitable method for the extraction of these oil from the flower is:

  1. distillation

  2. crystallisation

  3. distillation with reduced pressure

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

As the component is miscible with water vapour in vapour phase so steam distillation will be most suitable method for extraction.

Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

Glycerin can be purified by:

  1. vacuum distillation

  2. simple distillation

  3. steam distillation

  4. fractional distillation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The liquids which decompose at its boiling point can be purified by vacuum distillation. Glycerol decomposes at its boiling point (563K). It can be distilled by vacuum distillation without decomposition at 453K and under 12mm Hg pressure.
Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

Distillation under reduced pressure is generally used to purify those liquid which:

  1. have very low boiling points

  2. are volatile

  3. have high boiling points and which decompose below their boiling points

  4. have a large difference in their boiling points.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Distillation under reduced pressure lowers the boiling point of a liquid, which prevents the thermal decomposition of substances that are heat-sensitive. This technique is essential for liquids with high boiling points that would otherwise break down before reaching their boiling point at atmospheric pressure.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

_________ cannot be readily separated by physical means.

  1. Mixtures

  2. Metals

  3. Alloys

  4. Non-metals
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Alloys are metallic materials consisting of two or more elements combined in such a way that they cannot be readily separated by physical means. More than 90% of metals used are in the form of alloys.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

A mixture of sand and salt can be separated by:

  1. Sublimation

  2. Sieving

  3. Dissolving salt and sand mixture in water and then filtration

  4. Dissolving salt in water and then distillation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dissolving salt in water and then distillation
Process to separate sand and salt from the mixture :
Step 1: Add water to the mixture and stir until the salt dissolve.
Step 2: Turn your burner on and then keep the mixture over it.
Step 3: Pour the water mixture through a very fine strainer or cheese cloth filter . (Sand will remain in filter, salt and water will pass through it)
Step 4: Pour the water and salt mixture back into the burner . And allow the water to boil away and collect salt from there.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Which of the following  laboratory technique would not bring a physical change in the components of a mixture?

  1. Chromatography

  2. Precipitation

  3. Filtering

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

Physical change would not be in the components of a mixture by Filtering.
Filtering just separates solids from liquids. It does not involve any phase change.

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

Diffusion technique of separation can be used for :

  1. Separation of oxygen from air

  2. Recovery of hydrogen in oil refinery

  3. Separation of methane in bio gas

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

Gas mixtures can be effectively separated by synthetic membranes made from polymers such as poly-amide or cellulose acetate, or from ceramic materials. It can be used for separation of nitrogen or oxygen from air. Helps in Recovery of hydrogen in oil refinery processes. Also used in Separation of methane from the other components of bio gas.