Q. The number of unit cells in 58.5 g of $NaCl$ is nearly
A) $0.5 \times 10^{24}$
B) $1.5 \times 10^{23}$
C) $3\ \times 10^{22}$
D) $6\ \times 10^{20}$
Explanation
(b)
58.5 g $NaCl$ =1 mol $= 6.023\ \times \ 10^{23}$ $NaCl$ units
One unit cell contains 4 $NaCl$ units
Hence, number of unit cell present
$= \frac{6.023\ \times \ 10^{23}}{4} = 1.5 \times 10^{23}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.