An alloy of `Cu, Ag` and `Au` is found to have copper constituting the `c.c.p.` lattice. If `Ag` atom occupy the edge centres and `Au` atom is present at body centre, the formula of this alloy is `:`

Options

A. `Cu_4, Ag_2 Au`
B. `Cu_4Ag_4Au`
C. `Cu_4Ag_3 Au`
D. `CuAgAu`

Answer

C

Explanation

No. of Cu atoms = 4 (ccp arrangment)
No. of Ag atoms = 12 (edge) `xx 1/4 = 3`
No. of Au atoms = 1 (body centre)
Formula `Cu_4 Ag_3 Au`.