NEET Chemistry The Solid State Questions Solved

A solid PQ have rock salt type structure in which Q atoms are at the corners of the unit cell. If the body centred atoms in all the unit cells are missing, the resulting stoichiometry will be-

(A) PQ

(B) $P{Q}_{2}$

(C) ${P}_{3}{Q}_{4}$

(D) ${P}_{4}{Q}_{3}$

(C). In rock salt structure, atoms at the corner are also present at the face centres and hence

${Z}_{Q}=8×\frac{1}{8}+6×\frac{1}{2}=4$

And, the atoms at body centre also present at edge centres. But from question, body centres are missing and hence

${Z}_{p}=12×\frac{1}{4}=3.$

$\therefore$ Formula of resulting solid - ${P}_{3}{Q}_{4}$.

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