Tag: filtration and crystallisation

Questions Related to filtration and crystallisation

Pure solid can be obtained from its impure sample by :

chemistry separation of matter filtration and crystallisation other methods of separation separation techniques

  1. sedimentation

  2. crystallisation

  3. distillation

  4. decantation

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Correct Option: B
Explanation:

Pure solids can be obtained from its impure sample by crystallisation.
Crystallisation is used to purify solids.

Crystallisation is better than simple evaporation because :

chemistry separation of matter filtration and crystallisation other methods of separation separation techniques

  1. some impurities may remain in the solution after filtration

  2. some solids decompose or heating

  3. both A and B

  4. none of the above

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Correct Option: C
Explanation:

Some solids decompose or some, like sugar, may get charred on heating to dryness. Some impurities may remain dissolved in the solution even after filtration. On evaporation these contaminate the solid. So, crystallisation is better than evaporation.

In the process of crystallisation, crystals formed by different substances :

chemistry separation of matter filtration and crystallisation other methods of separation separation techniques

  1. are of same shapes and colours

  2. are of different shapes and colours

  3. shape and colour depends upon the amount of solute present

  4. can't be predicted

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Correct Option: B
Explanation:

Different substances form crystals of different shapes and colours.

When a mixture of common salt and ammonium chloride is heated, white fumes are liberated which change into a white deposit when cooked. What is this substance?

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

  1. Ammonium chloride

  2. Common salt (sodium chloride)

  3. A mixture of ammonium chloride and common salt

  4. Ammonium sulphate

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Correct Option: A
Explanation:

When a mixture of common salt and ammonium chloride is heated, white fumes are liberated which changes into a white deposit when cooked. This white substance is ammonium chloride. Salt and Ammonium chloride are separated by the method of sublimation.

Mixute of ammonium chloride and sodium chloride can be seperated by :

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

  1. distillation

  2. chromatography

  3. sublimation

  4. all of the above

Show answer
Correct Option: C
Explanation:

Substances like camphor, ammonium chloride, naphthalene, benzoic acid, iodine sublime on heating.
$\underset{(Impure)}{Solid}    \xrightarrow{\Delta}     vapour     \xrightarrow{cool}    \underset{Sublimate}{solid(pure)}$

A mixture of barium sulphate and $H _2O$ can be separated by the method of filtration.

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

  1. True

  2. False

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Correct Option: A
Explanation:

A mixture of barium sulphate and $H _2O$ can be separated by the method of filtration. Barium sulphate is insoluble in water.  During filtration, barium sulphate remains on the filter paper and water passes as through filter paper as filtrate.

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

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

  1. Ductility

  2. Opacity

  3. Density

  4. Solubility

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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.

What is meant by sublimation?

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

  1. Conversion of solid into liquid on heating

  2. Conversion of solid into gas on heating

  3. Conversion of liquid into gas on heating

  4. Change of shape of solid on heating

Show answer
Correct Option: B
Explanation:

Sublimation is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase. Sublimation is easier for volatile materials which can be evaporated at low temperatures.


Hence, the correct option is $B$

Sublimation is used to separate :

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

  1. two liquids having different boiling points

  2. two liquids having same melting point

  3. volatile and non volatile solids

  4. volatile solids having same melting point

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Correct Option: C
Explanation:

Sublimation is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase.

Which of the following shows sublimation on heating?

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

  1. Solids

  2. Liquids

  3. Gases

  4. All of these

Show answer
Correct Option: A
Explanation:

Sublimation is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase.