Tag: separation methods

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Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Naphthalene is a volatile solid. It is best purified by:

  1. Crystallisation

  2. Distillation

  3. Steam distillation

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

Sublimation is the process in which a particular solid is converted into gas without changing into liquid. Naphthalene is volatile. It sublimates at room temperature without converting into liquid.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Sublimation is a process in which a solid.

  1. Changes into another allotropic form

  2. Changes into liquid form

  3. Changes into vapour form

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

Examples:

  •  "Dry ice" or solid carbon dioxide sublimes.
  •  Snow and ice can sublime in the winter months without melting.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

A mixture of water and NaCl can be separated by?

  1. Sublimation

  2. Evaporation

  3. Decantation

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

Salt dissolves in water. There is a high difference in their boiling point, so evaporation can be used to remove the water to obtain salt. The water vapours that evaporates can be condensed to form water. Salt is left behind as residue during evaporation.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

How are the following separated ?
Lead sulphate from a mixture of lead sulphate and lead chloride ?

  1. distillation

  2. filtration

  3. chromatography

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

Lead sulphate is insoluble in water whereas lead chloride is soluble. By dissolving the mixture of lead sulphate and lead chloride in water we can separate the two. After dissolving the mixture in water, lead sulphate can be obtained as the solid that's left behind. Lead chloride can be recovered by evaporating the solution.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Name a technique used to separate : Iodine and alcohol

  1. filtration

  2. distillation

  3. evaporation

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

Iodine dissolved in alcohol is called tincture of iodine. Alcohol is a volatile liquid. So the mixture can be kept open or warmed in a water bath. Alcohol will evaporate leaving behind the iodine crystals.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

Ammonium chloride is separated from a mixture of sodium chloride and ammonium chloride by the process of _____________.

  1. Crystallization

  2. Filtration

  3. Sublimation

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

There are way in separating mixtures of chloride salts such as that of sodium chloride and ammonium chloride. It can be done by crystallization, filtration, and sublimation. The easiest method among the three is separation by sublimation.  Ammonium chloride sublimes upon heating. Actually, the sublimation is a decomposition of ammonium chloride forming ammonia and hydrogen chloride. Sodium chloride, on the other hand, doesn't sublime and has a higher melting point than ammonium chloride. If we want to separate the mixture, we have to heat up to 330-350 degrees Celsius and collect the gas that will be produced. 

Hence, the correct option is D.

Multiple choice chemistry separation of matter sedimentation, decantation and filtration other methods of separation separation methods

The process by which a mixture of sodium chloride and ammonium chloride can be separated, is called :

  1. sublimation

  2. chromatography

  3. evaporation

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

Sublimation is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase.
To separate mixtures that contain a sublimate with volatile component from a non-sublimate impurity, the sublimation process is used. Ammonium chloride changes directly from solid to gaseous state on heating. The gaseous form of ammonium chloride can be cooled easily to get a pure solid.