Q. A solid has structure in which ‘W’ atoms are located at the corners of a cubic lattice ‘O’ atoms at the centre of edge and Na atoms at the centre of cube. The formula for the compound is
A) $Na_{2}WO_{3}$
B) $Na_{2}WO_{2}$
C) $NaWO_{2}$
D) $NaWO_{3}$
Explanation
(d)
In a unit cell, W atoms at the corner
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \frac{1}{8} \times 8 = 1$
O-atoms at the centre of edge
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \frac{1}{4} \times 12 = 3$
W : O : Na = 1 : 3 : 1
Hence, formula $= NaWO_{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.