What is meant by Vapour phase refining? Write any one example of the process which illustrates this technique, giving the chemical equations involved.
Answers
Vapour phase refining
Explanation:
Vapour phase refining is a refining method. The method that is to be refined is converted to a volatile form and collected. It is then decomposed to yield pure metal. For this method to be used, the metal should form a volatile compound with a reagent and you should be able to decompose the volatile compound so formed. Only then, recovery will be possible.
Example: Mond’s Process for refining of Nickel
Ni + 4CO --> Ni(CO)4 at 330K - 350K
Nickel is heated in a stream of carbon monoxide to form a volatile complex called nickel tetracarbonyl.
Ni(CO)4 --> Ni +4(CO) at 450K - 470K
This complex is decomposed at a higher temperature to obtain pure metal.
Answer: Vapour Phase Refining is a type of refining process based on the principle that the impure metal is converted into a volatile compound and which can be collected elsewhere. It is then decomposed used to give back the pure metal.
Ni+4C0 ----> {330-350k}Ni(CO)_{4}</tex><tex>Ni(CO)_{4}\xrightarrow {450-470k}Ni+4CO</tex>
Explanation: