Discussion Forum



1)

 An alloy  of copper , silver and gold is found to have copper atom constiuting the ccp lattice. If silver atom occupy the edge centres and gold atom is present at body centred, the alloy has a formula 


A) $Cu_{4}Ag_{2}Au$

B) $Cu_{4}Ag_{4}Au$

C) $Cu_{4}Ag_{3}Au$

D) $Cu_{}Ag_{}Au$

Answer:

Option C

Explanation:

 In the unit  cell number of Cu atoms (fcc/ccp)

= $8\times\frac{1}{6}+6\times\frac{1}{2}=4$

 As Ag atoms occupying edge centred = $12\times\frac{1}{4}=3$

 and Au  atoms are presents at the body centred=1

 $\therefore$  formula , $Cu_{4}Ag_{3}Au$