(a) Write the principle involved in the vapour phase refining of metals. (b) Write the name of the metal refined by each of the following processes : (i) Mond process (ii) van Arkel method (c ) What is the role of depresent in froth floatation process ?

(a) Write the principle involved in the vapour phase refining of metal

1.	(a) Write the principle involved in the vapour phase refining of metals. (b) Write the name of the metal refined by each of the following processes : (i) Mond process (ii) van Arkel method (c ) What is the role of depresent in froth floatation process ?
Answer» (a) Vapour phase refining : In this method, crude metal is freed from impurities by first converting it into a suitable volatile compound by heating it with a specific reagent at a lower temperature and then decomposing the volatile compound at some higher temperature to give pure metal. (c ) Depressant is to prevent one type of sulphide ore particles from forming the froth with air bubbles. Example : NaCN is used as a depressant to separate lead sulphide (PbS) ore from Zinc Sulphide (ZnS). `4NaCN + ZnS rarr underset("Prevent from forming the forth)")underset("(Complex formed and")(NO_(2)[Zn(CN_(4))]+Na_(2)S)`

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(a) Write the principle involved in the vapour phase refining of metals. (b) Write the name of the metal refined by each of the following processes : (i) Mond process (ii) van Arkel method (c ) What is the role of depresent in froth floatation process ?

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