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Solvent extraction - class-VII

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A mixture contains two solids A and B. Solid A is light in weight while solid B is very heavy. Their sizes are almost same. Here, A is the unwanted component. To get pure solid B, which separation method would you suggest?

  1. sieving

  2. winnowing

  3. magnetic separation

  4. filtration


Correct Option: B
Explanation:

Winnowing is a traditional method in water air current is blown to separate particles of light weight and heavier weight.

Which of the following mixtures will be the most difficult do separate?

  1. Iron filings + sand

  2. Sand + water

  3. Saw dust + stones

  4. Nitrogen + hydrogen


Correct Option: D
Explanation:

Nitrogen and Hydrogen gets react and converted into ammonia their occurs a chemical change hence separation of nitrogen and hydrogen is most difficult.

Benzene and water can be separated by

  1. Separating funnel

  2. Sublimation

  3. Fractional distillatioln

  4. Filtration


Correct Option: A
Explanation:

Benzene and water are immiscible, liquids. They can be separated by separating funnel.

To separate ammonium chloride from common salt, we use:

  1. filtration

  2. sedimentation

  3. sieving

  4. sublimation


Correct Option: D
Explanation:

Sublimation is a specialized change of state when a solid substance skips the liquid phase and moves directly into the gas phase. This occurs because the substance absorbs energy so quickly from the surroundings that melting never occurs.

Ammonium chloride separated from common salt by sublimation process.

Sand and water can be separated by:

  1. decantation

  2. sieving

  3. sublimation

  4. magnetic separation


Correct Option: A
Explanation:

Decantation is a process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension. Sand from water can be separated by decantation.

You can use decantation to separate:

  1. two miscible liquids

  2. two immiscible liquids

  3. two metals in an alloy

  4. solid-solid mixture


Correct Option: B
Explanation:

Decantation is a process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension. Example sand from water can be separated by decantation.

A small boy mischievously mixed small pebbles into a bag of pulses. What method will you employ to separate the mixture?

  1. Magnetic separation

  2. Crystallisation

  3. Handpicking

  4. Filtration


Correct Option: C
Explanation:

The method in which substances in a mixture can be separated by just picking them out with the help of hand from the mixture is known as handpicking method. It is one of the various methods which are carried out in dry conditions.

Greasy spots can be removed from clothes by:

  1. evaporation

  2. sublimation

  3. fractional distillation

  4. dissolving in a suitable solvent


Correct Option: D
Explanation:

Greasy spots can be removed from clothes by dissolving them in a suitable solvent. For example, aqueous ammonia is used in laundries as a solvent for removing grease and oil stains.


Hence, option D is correct.

Wheat flour can be separated from wheat bran by:

  1. hand picking

  2. sieving

  3. winnowing

  4. filtration


Correct Option: B
Explanation:

Sieving is a device for separation of particles based on their size difference,

so, wheat flour can be separated from wheat bran by sieving.

Seperation of two immiscible liquids is based on :

  1. difference in the solubility of the two liquids

  2. difference in the densities of the two liquids

  3. difference in melting point of the two liquids

  4. difference in boiling point of the two liquids


Correct Option: B
Explanation:

Separation of two immiscible liquids is based on difference the densities of the two liquids. The method is used for separating two immiscible liquids, such as oil and water.

While separating oil and water, which component forms the upper layer ?

  1. Oil

  2. Water

  3. Both A and B

  4. Air


Correct Option: A
Explanation:

Oil being lighter than water forms the upper layer and water forms the lower layer.

Winnowing is used only for:

  1. homogeneous solid-solid mixtures

  2. homogeneous solid-liquid mixtures

  3. heterogeneous solid-liquid mixtures

  4. heterogeneous solid-solid mixtures


Correct Option: D
Explanation:

In order to separate $2$ heterogenous solid,Solid mixture in which particles having different masses can be separated by winnowing.

Ex. Wind winnowing is an agricultural method developed by ancient cultures for separating grain from chaff.

A vendor sells white powdered salt mixed with white powdered stone. The knowledge of which property will help you detect this malpractice?

  1. Ductility

  2. Opacity

  3. Density

  4. Solubility


Correct Option: D
Explanation:

The purity of the solid salt sample can be anaylsed simply by checking its solubility in proper solvent,

choose a proper solvent and add a pinch of compound to it, if the compound is completely soluble that means compound is pure.

In a separating funnel, one phase is ______ and other phase is :              .

  1. Aqueous phase, organic phase

  2. Aqueous phase, inorganic phase

  3. Inorganic phase, organic phase

  4. None of above


Correct Option: A
Explanation:

A separating funnel is used for the separation of components of a mixture between two immiscible liquid phases. One phase is the aqueous phase and the other phase is an organic solvent. This separation is based on the differences in the densities of the liquids. The liquid having more density forms the lower layer and the liquid having less density forms the upper layer.

We sprinkle water in a dirty room before sweeping because:

  1. water makes sweeping easier

  2. water repels dust particles

  3. water coagulates the dust particles

  4. sprinkling water is fashionable


Correct Option: C

A mixture of oil and water is separated by:

  1. Filtration

  2. Using separating funnel

  3. Sublimation

  4. Fractional distillation


Correct Option: B
Explanation:

Mixture of oil and water forms a heterogenous mixture with oil settled on top of water due to density variation. This can be separated using a separting funnel.

Oil and water are miscible liquids.

  1. True

  2. False


Correct Option: B
Explanation:

The error in the given statement is miscible.

The correct statement is oil and water are immiscible liquids.

Mixture of ${\text{Al}}{\left( {{\text{OH}}} \right) _3}\,\,{\text{and}}\,\,{\text{Fe}}{\left( {{\text{OH}}} \right) _3}$ can be separated by

  1. ${\text{HCl}}\,$

  2. ${\text{N}}{{\text{H}} _{\text{4}}}{\text{OH}}\,$

  3. ${\text{NaOH}}$

  4. ${\text{HN}}{{\text{O}} _{\text{3}}}$


Correct Option: A

Separation of $CCl 4$ from $CS _2$ can be carried out by ______ method.

  1. fractional distillation

  2. separating funnel 

  3. crystallization

  4. decantation


Correct Option: B
Explanation:

Separation of $C{Cl} _{4}$ from $C{S} _{2}$ can be carried out by careful distillation in presence of inert gas stream thus can be carried out by separating funnel method.


Two immiscible liquids are separated by?

  1. Separating funnel

  2. Fractional distillation

  3. Chromatography

  4. Sublimation


Correct Option: A
Explanation:

Separating immiscible liquids is done simply using a separating funnel. The two liquids are put into the funnel and are left for a short time to settle out and form two layers. The tap of the funnel is opened and the bottom liquid is allowed to run. The two liquids are now separate.

Name a technique used to separate : Petrol and water

  1. distillation

  2. separating funnel

  3. sublimation

  4. chromatography


Correct Option: B
Explanation:

Use a separating funnel since the petrol floats above the water.Just let the mixture stand. Petrol and water are not soluble, so they will eventually separate. Since the petrol is lighter than the water, it will form a layer on top, and may be drawn off.Petrol will form at the top of water as it is not as heavy. 

Filtration as a method of separation can be used for mixtures that are :

  1. homogeneous and liquid-in-gas mixtures

  2. heterogeneous and liquid-in liquid mixtures

  3. hogeneous and solid-in-liquid mixtures.

  4. heterogeneous and solid-in liquid mixtures


Correct Option: D
Explanation:

Filtration is generally used for heterogeneous solution or solution which are partially miscible or immisscible, or in solid liquids phase.

The process of settling down of heavier, insoluble particles in an undisturbed mixture solution is called:

  1. filtration

  2. centrifugation

  3. sedimentation

  4. decantation


Correct Option: C
Explanation:

Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration, or electromagnetism.

A very large quantity of mixture contains tiny particles of three different substances X, Y, and Z. They are of the same size, cubical in. shape and yellow in color. X particles are very heavy, insoluble, non-magnetic and contribute $50\, \%$ of the mixture. Y particles are very light, insoluble, non-magnetic and contribute $40\, \%$ of the mixture. And Z particles are actually iron pieces. Which of the following methods can separate X, Y, and Z in the fastest manner?

  1. Winnowing-Magnetic separation

  2. Magnetic separation-Winnowing

  3. Sieving-Magnetic separation Filtration

  4. Handpicking - Sublimation-Sieving


Correct Option: A
Explanation:

By Winnowing process heavy particles can be easily separated by blowing off the lighter particles with the help of air. Here Y is light and gets separated by winnowing. Then X and Z can be separated by the magnetic separation method because Z is magnetic.

The components of a mixture can be separated only by chemical means.

Write true or flase.

  1. True

  2. False


Correct Option: B
Explanation:

The components of a mixture can be separated by physical means.

Hence option-B is correct.

Heavy water is called as heavy because it:

  1. is denser than common water

  2. is an oxide of deuterium

  3. has a heavy or bad test

  4. none of these


Correct Option: B
Explanation:

Heavy water in which deuterium, a heavy isotope of hydrogen, takes the place of hydrogen. Heavy water has physical and chemical properties that are like those of ordinary water, but heavy water is 10 percent heavier and has higher freezing and boiling points.


Hence, option B is correct.

Some iron fillings are mixed with sand. We can separate them using magnetic separation method. This method is applicable only when:

  1. magnetic substances are mixed up with non-magnetic substances

  2. magnetic substances are mixed up with magnetic substances

  3. magnetic substances are heated beyond their Curie temperatures

  4. two magnetic substances have equal melting points


Correct Option: A
Explanation:

Magnetic separation is a process in which magnetically susceptible material is extracted from a mixture using a magnetic force. This separation technique can be useful in mining iron as it is attracted to a magnet.When magnetic substances are mixed with non-magnetic substances.

Wheat flour is separated from wheat bran by the method of:

  1. handpicking

  2. sieving

  3. winnowing

  4. filtration


Correct Option: B
Explanation:

The method of separation of particles from a mixture based on the difference in size of particles is known as sieving. It uses sieve plates for separation of coarse particles from finer particles. Wheat flour is separated from wheat bran by the method of sieving.

Choose the substance that is used as a filter.

  1. Oil paper

  2. Silicon dioxide

  3. Unglazed porcelain

  4. Plastic


Correct Option: C
Explanation:
Unglazed porcelain can be used as filters because it has small poses which filter some dirt.

The methods of separation used in municipal water works are:

  1. loading, sedimentation, decantation and filtration

  2. sedimentation, filtration and distillation

  3. loading, decantation, sieving and distillation

  4. sedimentation, centrifugation and distillation


Correct Option: A
Explanation:

The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light.

Which of the following solvents is used for separation of mixture of sand and sulphur?

  1. Water

  2. Benzene

  3. Carbon di sulphide

  4. Ethyl alcohol


Correct Option: C
Explanation:

The separation is carried out by using organic solvent carbon disulphide in which sulfur is soluble. Sand is insoluble and can be filtered out. The remaining solution is exposed to atmosphere from which carbon disulphide will gradually evaporate and sulfur is recovered back from the solution.

How is scrap-iron separated from other wastes in a scrap yard?

  1. Sublimation

  2. Magnetic separation

  3. Handpicking

  4. Winnowing


Correct Option: B
Explanation:

Waste materials supplied to factories contain a number of scrap metals including iron ore. so, in factories, scrap iron is separated from the heap of waste materials by using big electromagnets fitted to a crane. 

Winnowing is used to seperate:

  1. homogenous solid-solidmixtures

  2. homogenous solid-liquid mixtrures

  3. heterogenous solid-liquid mixtures

  4. heterogenous solid-solid mixtures


Correct Option: D
Explanation:

In order to separate $2$ heterogenous solid,Solid mixture in which particles having different masses can be separated by winnowing.

Ex. Wind winnowing is an agricultural method developed by ancient cultures for separating grain from chaff.

Sand and water are separated by the method of:

  1. sieving

  2. sublimation

  3. magnetic separation

  4. decantation


Correct Option: D
Explanation:

As sand does not mix water. sand settles down like precipitates. so you can decant it from water. and water can be filtrated to get more clean water.

Decantation is a process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension.

In a separating funnel, organic phase is always _______ aqueous phase.

  1. Above

  2. Below

  3. Mixed together

  4. Both a and b


Correct Option: A
Explanation:

A separatory funnel, also known as separation funnel, is a piece of laboratory glassware used in liquid-liquid extractions to separate (partition) the components of a mixture into two immiscible solvent phases of different densities. Most organic solvents float on top of an aqueous phase, though important exceptions are most halogenated solvents

X and Y are liquids with unequal densities. Which method can be employed to separate them?

  1. Centrifugation

  2. Chromatography

  3. Distillation

  4. Separating funnel


Correct Option: D
Explanation:

Separating funnel is an effective method where two liquids that do not dissolve very well in each other (immiscible liquids) can be separated by taking advantage of their unequal density. 

What seperation technique will you use for seperating:


(a) Oil from water
(b) Tea leaves from tea
(c) Wheat grains from husk

  1. a = filtration, b = Winnowing, c = Separating funnel

  2. a = Winnowing, b = filtration, c = Separating funnel

  3. a = Separating funnel, b = filtration, c = Winnowing

  4. a = Separating funnel, b = Winnowing, c = filtration


Correct Option: C

A student accidentally poured a blue liquid into a beaker of water in the laboratory. The blue liquid is immiscible in water and is denser than water. What must he use to separate the 2 liquids?

  1. Filter Funnel

  2. Displacement Can

  3. Separating Funnel

  4. Distilling Flask


Correct Option: C
Explanation:

In separating funnel two liquids are separated depending upon their relative density. The liquid which is denser settles down below which can be separated and the liquid having lower density settled above.

We can separate alcohol dissolved in water by using a separating funnel.

  1. True

  2. False


Correct Option: B
Explanation:

As water and alcohol are miscible so we can not separate them using separating funnel and distillation is used to separate them.

A mixture of chloroform and water taken in a separating funnel is mixed and left undisturbed for some time. The upper layer in the separating funnel will be:

  1. chloroform

  2. water

  3. mixture of both

  4. none of these


Correct Option: B
Explanation:

As density of water is less than chloroform so upper layer will be of water while lower layer contains chloroform.

Which of the following is the seperation technique to seperate mercury and water?

  1. Seperating funnel

  2. Sublimation

  3. Filteration followed by evaporation

  4. Seperating funnel followed by evaporation or distillation


Correct Option: A
Explanation:

We can separate them using separating funnel because the two are immiscible and mercury is denser than water.

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