NEET Chemistry The Solid State Questions Solved

NEET - 2008

Which of the following statements is not correct?

(a) The fraction of the total volume occupied by the atoms in a primitive cell is 0.48

(b) Molecular solids are generally volatile

(c) The number of carbon atoms in an unit cell of diamond is 4

(d) The number of Bravais lattices in which a crystal can be categorized is 14

Concept Videos :-

#5 | Simple Cubic Unit Cell: Coordination Number
#10 | FCC Unit Cell: Coordination Number
#15 | Tetrahedral Voids
#16 | Octahedral Voids
#17 | Position of Tetrahedral Voids in FCC
#18 | Position of Octahedral Voids in FCC
#19 | Hexagonal Primitive (HP) Unit Cell
#22 | Coordination Number of HP Unit Cel
#23 | Radius Ratio

Concept Questions :-

Voids and radius ratio/coordination number

Key Idea:- Packing fraction of lattice structure or fraction of total volume occupied
Volume occupied by atoms in a unit cell
               Volume of the unit cell

Packing fraction of simple cube
= Zx4/3 πr3   = 1x4/3 πr3
         a3                  (2r)3

(∴ For primitive cell a=2r)

∴ Volume occupied=52%

Difficulty Level:

  • 47%
  • 19%
  • 26%
  • 10%
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