An alloy of copper, silver and gold is found to have copper constituting the face-centred cubic (FCC — Solid State Chemistry Question

💡 Solution & Explanation

Cu at FCC lattice points contributes $8 \times (1/8) + 6 \times (1/2) = 4$ atoms. Ag at edge centres contributes $12 \times (1/4) = 3$ atoms. Au at body centre contributes $1 \times 1 = 1$ atom. The formula is $Cu_4Ag_3Au$. Therefore, correct answer is C.