CBSE Class 12th Chemistry Chapter1 The Solid State -Part16

Class XII Chemistry Chapter 1 The Solid State NCERT Solution is given below.

Question 1.11:
Name the parameters that characterize a unit cell.
Answer
The six parameters that characterise a unit cell are as follows.
(i) Its dimensions along the three edges, a, b, and c
These edges may or may not be equal.
(ii) Angles between the edges
These are the angle ∝ (between edges b and c), β (between edges a and c), and γ (between edges a and b).

Question 1.12:
Distinguish between
(i)Hexagonal and monoclinic unit cells
(ii) Face-centred and end-centred unit cells.
Answer
(i) Hexagonal unit cell
For a hexagonal unit cell,


(ii) Face-centred unit cell
In a face-centred unit cell, the constituent particles are present at the corners and one at the centre of each face.
End-centred unit cell
An end-centred unit cell contains particles at the corners and one at the centre of any two opposite faces.