Question

unit cell of NaCl contains 4 NaCl molecule. If the density of NaCl crystal is2. 17 g/cm³.Find the edge length of the cube . ​

Answer 1

Answer:

Theoretical density of a crystal, ρ=  

N  

o

​  

a  

3

 

nM

​  

 g/cm  

3

 

Now, For NaCl, n=4 , ρ=2.17 g/cm  

3

, M=23+35.5=58.5 g

a  

3

=  

ρ N  

o

​  

 

nM

​  

=  

2.17×6.022×10  

23

 

4×58.5

​  

 

⇒a  

3

=17.9×10  

−23

=179×10  

−24

 

⇒a=5.63×10  

−8

 cm

Explanation: