Consider the following metallurgical processes`:`
`(I)` Heating impure metal with `CO` and distilling the resulting volatile carbonyl `(b.p. 43^(@)C)` and finally decomposition at `150^(@)-200^(@)C` to get the pure metal.
`(II)` Heating the sulphide ore in air until a part is converted to oxide and then further heating in the absence of air to let the oxide react with unchanged metal sulphide.
`(III)` Electrolysis of the molten electrolyte containing approximately equal amounts of the metal chloride and NaCl to obtain the metal.
The processes used for obtaining magnesium , nickel and copper are respectively.

Options

A. (I),(II) and (III)
B. (II), (III) and (I)
C. (III), (I) and (II)
D. (II), (I) and (III)

Answer

C

Explanation

(I) `underset(("impure"))(Ni)+4CO overset(50^(@)C)to underset(("volatile"))([Ni(CO_(4))]) overset(230^(@)C) to underset(("pure"))(Ni)+4CO uarr`
`(II) Cu_(2)S+(3)/(2) overset(Delta)to Cu_(2)O+SO_(2)`
`Cu_(2)S+2Cu_(2)O underset("temp".)overset("high")to 6Cu+SO_(2)`
`(III) MgCl_(2)(s) overset("electrolysis")to Mg^(2+)(l)+2Cl^(-)(l)`
At cathode : `Mg^(2+)+2e^(-) to Mg(s)`
At anode : `2Cl^(-)(l)to Cl_(2)(g)+2e^(-)`