Question

A molecule contains atoms x and y so that  x occurs at the corners of the cube while y at the face centres. The formula of the molecule can be

(a) xy₃

(b) x₃y

(c) xy₂

(d) x₂y

Answer 1

Correct option (a) xy₃

Explanation:

x atoms are at the corners of the cube, therefore, 

number of x-atoms per unit cell = 1/8 x 8 = 1

y-atoms are at the face centres of cube

:. Number of y-atoms per unit cell = 1/2 x 6 = 3

The formula of the molecule is xy₃