Complex formed in the following methods are
(I) Mond's process for purification of nickel
(II) Removal of lead poisoning from the body
(III) Cyanide process for extraction of silver
(IV) Froth flotation process for separation of `ZnS` from galena ore by using depresent.

Options

A. 1. `Ni(CO)_(4)" "[Pb(EDTA)]^(2-)" "[Ag(CN)_(2)]^(-)" "[Zn(CN)_(2)]`
B. 2. `Ni(CO)_(4)" "[Pb(EDTA)]^(2-)" "[Ag(CN)_(2)]^(-)" "[Zn(CN)_(4)]^(2-)`
C. 3. `Ni(CO)_(4)" "[Pb(EDTA)]^(4-)" "[Ag(CN)_(2)]^(-)" "[Zn(CN)_(6)]^(4-)`
D. 4. `Ni(CO)_(4)" "[Pb(EDTA)]^(2-)" "[Ag(CN)_(2)]^(3-)" "[Zn(CN)_(4)]^(2-)`

Answer

B

Explanation

`Ni+4CO to Ni(CO_(4))`
`Pb^(2+)+EDTA^(4-) to [Pb(EDTA)]^(2-)`
`Ag+CN^(-)+O_(2) to [Ag(CN)_(2)]^(-)+OH^(-)`
`Zn^(2+)+4CN^(-) to [Zn(CN)_(4)]^(2-)`