NEET Chemistry The Solid State Questions Solved


What is the simplest formula of a solid whose cubic unit cell has the atom A at each corner, the atom B at each face centre and a C atom at the body centre-

(A) AB2C                                         

(B) A2BC

(C) AB3C                                         

(C) ABC3

(C). An atom at the corner of a cube is shared among 8 unit cells. As there are 8 corners in a cube, number of corner atom (A) per unit cell = 8×18=1.

A face-centered atom in a cube is shared by two unit cells. As there are 6 faces in a cube, number of face centred atoms (B) per unit cell = 6×12=3.

An atom in the body of the cube is not shared by other cells.
 Number of atoms (C) at the body centre per unit cell = 1
Hence, the formula of the solid is AB3C.

Difficulty Level:

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