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प्रश्न
What criterion is followed for the selection of the stationary phase in chromatography?
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उत्तर १
The stationary phase is selected in such a way that the components of the sample have different solubilities in the phase. Hence, different components have different rates of movement through the stationary phase and, as a result, can be separated from each other.
उत्तर २
A material that has a strong ability to absorb contaminants should be used as the stationary phase. Additionally, the stationary phase should have a higher capacity to adsorb contaminants than the element that needs to be cleaned. This will make it easier for the element to elute.
संबंधित प्रश्न
Name the method used for the refining of zirconium.
What is the principle behind the zone refining of metals?
Explain the principle of the method of electrolytic refining of metals. Give one example.
Explain:
Zone refining
Name the common elements present in the anode mud in electrolytic refining of copper. Why are they so present?
Describe ‘froth floatation process’ for concentration of sulphide ore.
Out of PbS and PbCO3 (ores of lead), which one is concentrated by froth floatation process preferably?
Indicate the principle behind the method used for the refining of Nickel.
Outline the principles behind the refining of metals by the following methods:
Chromatographic method
Write the principle behind the following methods of refining:
Vapour-phase refining
Electrolytic refining is used to purify which of the following metals?
In which of the following method of purification, metal is converted to its volatile compound which is decomposed to give pure metal?
(i) Heating with stream of carbon monoxide.
(ii) Heating with iodine.
(iii) Liquation.
(iv) Distillation.
How are metals used as semiconductors refined? What is the principle of the method used?
Match the items of Column I with the items of Column II and assign the correct code:
| Column I | Column II |
| (A) Coloured bands | (1) Zone refining |
| (B) Impure metal to volatile complex | (2) Fractional distillation |
| (C) Purification of Ge and Si | (3) Mond Process |
| (D) Purification of mercury | (4) Chromatography |
| (5) Liquation |
Assertion: Zirconium can be purificed by Van Arkel method.
Reason: ZrI4 is volatile and decomposes at 1800 K.
Assertion: Zone refining method is very useful for producing semiconductors.
Reason: Semiconductors are of high purity.
Assertion: Hydrometallurgy involves dissolving the ore in a suitable reagent followed by precipitation by a more electropositive metal.
Reason: Copper is extracted by hydrometallurgy.
Describe a method for refining nickel.
Describe a method for refining nickel.
Describe a method for refining nickel.
