Applications of Crystallisaion

Q.

The colour of copper sulphate solution is

1. Green

2. Blue

3. Pink

4. Colourless

Q.

Crystals of Copper sulphate are heated for some time. What is the color of the crystals before and after heating?

Q.

What is the purification method used for an impure sample of Naphthalene?

Q.

How can we separate a mixture of sulphur and sugar?

1. By the process of filtration

2. By evaporation

3. By the process of crystallisation

4. By dissolving in carbon disulphide solution

Q.

How will you obtain a pure sample of copper (II) sulphate from an impure sample?

Q.

If the copper sulfate crystal is made up of copper sulfate sol. So will the crystalline ever melt?

Q.

Rama heated a mixture of iron filling and sulfur in a hard glass test tube for some time till a grey black product was found. she cooled the test tube and then added 2 ml carbon disulfide to it and shook the content of the test tube.

The observation made by her was likely to be shown above

1. I

2. II

3. III

4. IV

Q.

Name the technique used to separate:
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt

Q.

How will you recover common salt from salt-water mixture?

1. By chromatography

2. By condensation

3. By centrifugation

4. By evaporation

Q.

What is meant by crystallization? How is copper sulfate purified from its impure sample by this method? Explain the procedure.

Q. Question 1 (a)
Which separation techniques will you apply for the separation of the following?
a. Sodium chloride from its solution in water.

Q.

In an experiment to separate the components of a mixture of sand, common salt and ammonium chloride, the component which will be removed by filtration is:

1. sand

2. common salt

3. ammonium chloride

4. none of these

Q.

Air under pressure is blown into the filtered water, this is the method used for purification of water. This process is called as ____________.

1. distillation

2. sterilization

3. aeration

4. sedimentation

Q.

The material which is added to water during purification process at the water works so as to disinfect it is :

(a) potassium permanganate (b) betadine (c) chlorine (d) potash alum

Q. In the treatment of water, solid impurities are allowed to settle to the bottom. This particular stage in the entire purification is called ___.

1. Chlorination
2. Sublimation
3. Sedimentation
4. Distillation

Q. Why is crystallisation is used for obtaining pure copper sulphate from an impure sample rather than evaporation?

1. All of the above
2. The impurities left after filtration may contaminate copper sulphate on evaporation.
3. Because crystallisation is comparatively faster
4. Because crystallisation is comparatively easier than evaporation

Q.

Addition of potash alum results in the purification of water. The phenomenon associated with this reaction is ____

1. Precipitation

2. Crystallization

3. Coagulation

4. Sterilization

Q.

Give reason why alum is used in purification of river water

Q.

What would you observe when crystals of copper (II) sulphate are heated in a test-tube strongly?

Q. Pure copper sulphate $\left(CuS{O}_4\right)$ can be obtained from an impure sample by :

1. crystallization
2. galvanization
3. sedimentation
4. centrifugation

Q. What would happen if you cool a saturated copper sulphate solution very slowly?

Q. Why is crystallization better than evaporation to dryness?

1. Solids get charred in evaporation
2. Solids get decomposed in evaporation
3. Impurities do not get removed in evaporation
4. All of above

Q. Which method is used to obtain copper sulphate from an impure sample?

1. Hand-picking
2. Fractional Distillation
3. Crystallisation
4. None of the above

Q. Crystallisation is better than simple evaporation because :

1. solid obtained after evaporation contains impurities
2. some solids decompose on heating
3. both A and B
4. none of the above

Q.

1. Water Vapour

2. Binding Agent

3. Water Of Crystallization

4. Reaction Product

Q. Pure solid can be obtained from its impure sample by the process of:

1. sedimentation
2. crystallisation
3. filtration
4. decantation

Q. Crystals of pure copper sulphate are separated from the solution by :

1. condenstaion
2. distillation
3. solidification
4. filtration

Q. Common salt can be purified by a process of :

1. crystallization
2. homogenisation
3. boiling
4. distillation

Q. The process of separation of an organic compound from its aqueous solution by shaking with a suitable solvent is termed solvent extraction or differential extraction.
The organic compound present in aqueous layer moves to the organic solvent because:

1. the organic substance is more soluble in the organic solvent
2. organic solvent is insoluble in water hence organic compound moves up
3. from the supersaturated aqueous solution the solute starts diffusing
4. organic compound being lighter moves in the upper layer

Q. The salt we get from sea water can have many impurities in it. These impurities can be removed by :

1. sedimentation
2. crystallisation
3. all of the above
4. centrifugation