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

Your comments:

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

Your comments:

Question 2 of 15

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

Edge centered cubic

Face centered cubic

Simple cubic

Body centered cubic

Your comments:

Question 3 of 15

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

60%

68%

88%

78%

Your comments:

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

Your comments:

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

Your comments:

Question 6 of 15

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

Tetrahedral void

Octahedral void

Face void

Simple void

Your comments:

Question 7 of 15

8. HCP structure is present in:

Ag

Cu and Mg both

Mg

Cu

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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)

Your comments:

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

Your comments:

Question 10 of 15

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

12

8

4

6

Your comments:

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%

Your comments:

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

Your comments:

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

Your comments:

Question 14 of 15

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

2

6

8

12

Your comments:

Question 15 of 15

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