Minerals from which metals can be extracted economically and easily are called ores.The extraction of metals from theirs ores involves the following processes.
(i)Concentration.
(ii)Calcination | roasting | leaching .
(iii)Reduction.
It is carried out be one of the following methods.
Silver is extracted from its native ore by :

Options

A. Formation of soluble complex by dilute solution of NaCN in
presence of air followed by the reduction with zinc
B. Formation of soluble complex by dilute solution of NaCN in
absence of air followed by the reduction with zinc
C. Roasting followed by the self reduction
D. Roasting followed by electrolytic reduction

Answer

A

Explanation

`O_2` oxidases silver to silver (I) ion which then prouduce soluble complex with `CN^(-)` ions .
`2Ag+4NaCN+1/2 O_2 +H_2O hArr 2Na[Ag (CN)_2]+2NaOH`.
`2Na[Ag (CN)_2]+ZntoNa_2[Zn(CN)_4]+ZntoNa_2[Zn(CN)_4]+Agdarr`