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 chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

Why is it difficult to separate salt and ammonium chloride mixture and sublimation is the only method to do so?

  1. Both are white in colour

  2. Both are soluble in water

  3. Both A and B

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

Both salt and ammonium chloride are white in colour and soluble in water. They can't be separated by any other method except sublimation.

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

In the procedure of sublimation, the inverted funnel in plugged with cotton, because __________.

  1. cotton stops external air to enter in funnel

  2. cotton helps in sublimation

  3. ammonium chloride is a evaporating substance, which directly evaporate on heating without converting into liquid phase.

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

During separation procedure of ammonium chloride from salt by evaporation an inverted funnel is used which is plugged with cotton boll, so that ammonium chloride do not evaporate.

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

In the process of separation of ammonium chloride from the salt, ammonium chloride molecule ________. 

  1. evaporate

  2. sublime

  3. crystallize

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

The ammonium chloride molecule in separation from salt sublime and get separated. This is a sublimation process which is used to separate two solids. Here salt being non-volatile does not undergo sublimation. 

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

Which of the following is not a way to separate the components of a mixture?

  1. Evaporation

  2. Electrolysis

  3. Chromatography

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

In Electrolysis, the current is passed through the solution and compound gets ionised, with electrolysis we can separate hydrogen and oxygen from pure water, but we can't use this method to separate components of a mixture.

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

Fractional crystallization is a method of refining substance based on difference on their:

  1. boiling point

  2. solubility

  3. hardness

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

In fractional crystallization, the component with low solubility will crysatllize first and one with high solubility will crystallize latter, so substances can be refined based on the difference on their solubility.

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

Solid-solid mixtures are separated by:

  1. Filtration

  2. Distillation

  3. Sublimation

  4. None of these
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

Physical separation techniques depend on the physical properties of the substance. These physical properties include physical state, solubility, boiling point, melting point, density, specific gravity, electrical and magnetic properties.

  1. Washing: Insoluble solids like noble metals and compounds like silica can be washed with water until all the other impurities leave them. Washing can also be done with organic solvents when there is a mixture with soluble impurities and insoluble compound.
  2. Decanting: When the densities of two liquids that are immiscible in one another are to be separated this method can be used. Separating funnel helps to separately collect the tow liquids. In case of solids the lighter solids can be separated by decanting it in water medium when both of the solids are not soluble. By blowing air also the separation can be done with very light and heavy solid mixtures.
  3. Distillation: Mixtures of liquids can be separated when their boiling points are different by this technique. The mixture is slowly heated in a distillation flask. The component having the low boiling point vaporizes first. The vapors are collected by condensing them in Leibig's condenser. Mixtures containing more than two liquids can also be separated by this technique but the difference in boiling points must be at least 20C between each of them. Distillation can also be used to separate dissolved salts from their aqueous solutions. Sea water is distilled by the Sun rays to form clouds which rain fresh water without salts. Mixture of gases are separated by reducing their temperature and converting all the gases in to liquid state. By gradational increasing of temperatures each liquified gas gets converted into gaseous state and can be separated.
  4. Fractional distillation: When the difference in the boiling points are nearby to each other and not much, a detailed distillation is carried out which is called fractional distillation. It is done in a column called fractionating column. Fractionating column allows the condensation of different solvents at different temperatures and sending back the mixture fraction in to the flask. Petroleum distillation is done in the fractionating column in to various components over a wide range of temperatures. Melting point differences can also be utilized in the same way as boiling point in separation of mixtures. Icebergs are formed which are solidified fresh water is based on the depression of freezing point phenomenon.
  5. Solubility: Different compounds have different amounts of solubility at a certain temperature. When no more solid is soluble in solvent at a particular temperature it is called its saturation point at that temperature. In a mixture if one component is more soluble and the other less at a given temperature, they can be separated by this technique.
  6. Electrical and Magnetic separation: Electrolytes and non electrolytes, magnetic and non magnetic substances can be separated by this technique of separation using either electrical field or magnetic field.

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

Name a technique used to separate : Sodium chloride and sugar.

  1. filtration and evaporation

  2. filtration and distillation

  3. filtration and sublimation

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

sugar is organic,(contains carbon) and is soluable in organic solvents like alcohol. Salt is insoluable in alcohol. 
Add alcohol to the mixture, filter out the salt, then evaporate the alcohol and the sugar will be left.

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

Apart from salt and ammonium chloride, which other mixture can be separated by sublimation?

  1. Salt and napthalene

  2. Salt and sugar

  3. Sugar and ammonium chloride

  4. Sugar and anthracene
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation

Sublimation can be used to separate all those substances which can sublimise easily like naphthalene, ammonium chloride and anthracene.

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

After sublimation of ammonium chloride, how can salt be separated from the filtrate?

  1. Condensation

  2. Chromtography

  3. Evaporation

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

Evaporation technique is used to separate salt from the filtrate. Common salt does not decompose during evaporation. As the water evaporates, fewer and fewer water molecules are present to keep the salt particles apart. The salt, therefore, recrystallizes and can be collected. 

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

A separating funnel is used to separate the components of a mixture of:

  1. iodine and sugar

  2. ethanol and water

  3. cooking oil and water

  4. ammonium chloride and iron filings
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A separating funnel is used to separate the components of a mixture of cooking oil and water. A separating funnel is used to separate the components of a mixture of two immiscible liquids. Cooking oil and water are two immiscible liquids.

Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

John tried to separate sugar from its solution using the evaporation method. However, he was unsuccessful. Which of the following is the likely reason?

  1. There was insufficient sugar in the solution

  2. He had forgotten to stir the solution during heating

  3. The sugar had decomposed

  4. The sugar had vaporised.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
John tried to separate sugar from its solution using the evaporation method. However, he was unsuccessful as the sugar had decomposed. When you sugar (sucrose) is heated, it undergoes dehydration. The crystalline structure breaks down. Molecules decompose into glucose and fructose and then lose water and polymerize to form caramel, which is a red-orange colored solid.
Multiple choice chemistry basic analytical techniques filtration and crystallisation other methods of separation separation techniques

Sand that is needed for a project has some common salt accidentally mixed with it. which of the following processes need to be used to separate sand and salt?
1. Filtration
2. Evaporation
3. Distillation
4. Crystallisation

  1. 1, 2

  2. 1,2 and 4

  3. 1, 2 and 3

  4. 1,2,3 and 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

To separate the mixture of salt and sand;

first we will make the aqueous solution, salt gets dissolved in water and sand particle remain undissolved,
so, the misture can be separated by filtration and evaporation.

Multiple choice evs modern agriculture agricultural practices in india different types of farming and agriculture various agricultural practices

The process that is used to separate grain from stalks etc.is called as 

  1. Separation

  2. Threshing

  3. Hand picking

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

The process that is used to separate grain from stalks etc. is threshing. In this process, the stalks are beaten to free the grain seeds.

So, the correct answer is 'threshing'