Solid State Question 12

Question: How many unit cells are present in 5.0 gm of crystal AB (formula mass of AB = 40) having rock salt type structure- ( $ N _{A} $ = Avogadro’s no.)

Options:

A) $ N _{A} $

B) $ \frac{N _{A}}{10} $

C) $ 4N _{A} $

D) none of these

Show Answer

Answer:

Correct Answer: D

Solution:

[d] 4 formula units of AB are present in a unit cell
$ \therefore $ no. of unit cell $ =\frac{4}{40}\times \frac{N _{A}}{4} $
$ \Rightarrow 0.025N _{A} $