Packing Efficiency, Class 12 Chemistry NCERT Solutions

1. There will be total 15 MCQ in this test.
2. Please keep a pen and paper ready for rough work but keep your books away.
3. The test will consist of only objective type multiple choice questions requiring students to mouse-click their correct choice of the options against the related question number.
4. No negative marking for incorrect choice.
5. Please click on “Finish the Test” when you want to exit.
6. All the best – Happy Studying

1. What is the volume occupied by spheres of a body centred cubic unit cell?

 A

 B

 C

 D

Question 1 of 15

2. What is the volume occupied by spheres with radius r in the simple cubic unit cell?

 A

 B

 C

 D

Question 2 of 15

3. For which type of cubic lattice, a = 2r?

 Edge centered cubic

 Face centered cubic

  Simple cubic

 Body centered cubic

Question 3 of 15

4. Packing efficiency of body centred cubic unit cell is:

 60%

 68%

 88%

  78%

Question 4 of 15

5. Packing efficiency in a unit cell is never 100% because constituent particles are assumed to be:

 Spheres

 Cuboid

 Cubes

 Conical

Question 5 of 15

6. If r is radius of void and R is radius of the sphere, then for an atom to ocuppy an octahedral void which relation holds true?

 r = 2.25 R

  r = 225 R

 r = 0.414 R

  r = 0.225 R

Question 6 of 15

7. Which type of void is represented by the following diagram?

 Tetrahedral void

 Octahedral void

 Face void

  Simple void

Question 7 of 15

8. HCP structure is present in:

 Ag

 Cu and Mg both

 Mg

 Cu

Question 8 of 15

9. If r is the radius of the void and R is the radius of the sphere, what is AC in the following diagram?

 AC = 2R

 AC = 2(r+R)

 AC = 2r

 AC = (r+R)

Question 9 of 15

10. Which of the following shows maximum packing efficiency?

 Hexagonal close packing

 Body centred cubic unit cell

  Same in all

 Simple cubic unit cell

Question 10 of 15

11. The number of atoms per unit cell in a face centred cubic arrangement is:

  12

 8

 4

 6

Question 11 of 15

12. The packing efficiency of the two-dimensional square unit cell shown below is

 39.27%

 74.05%

 78.54%

 68.02%

Question 12 of 15

13. Which of the following relations correctly correlates radius(r) with edge length(a) of a body centred unit cell?

 A

 B

 C

 D

Question 13 of 15

14. The number of atoms in each unit cell in ccp structure is:

  4 atoms

 5 atoms

 8 atoms

 6 atoms

Question 14 of 15

15. The number of atoms per unit cell in a body centred cubic arrangement is:

 2

 6

 8

  12

Question 15 of 15

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