If NaCl is doped with 10-4 mol % of SrCl2, the concentration of cation vacancies will be (NA = 6.023 x 1023 mol-1)                                                                             

1. 6.023 x 1015 mol-1             

2. 6.023 x 1016 mol-1

3. 6.023 x 1017 mol-1             

4. 6.023 x 1014 mol-1                                     

Subtopic:  Density & Packing Fraction |
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The phenomenon in which polar crystals on heating produce electricity is called:-
1. pyro-electricity
2. piezo-electricity
3. ferro-electricity
4. ferri-electricity

Subtopic:  Magnetic Behaviour of an Element/Compound |
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Metals have conductivity of the order of (ohm-1 cm-1):-

1. 1012

2. 108

3. 102

4. 10-6

Subtopic:  Density & Packing Fraction |
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Total volume of atoms present in a face centred cubic unit cell of a metal is ( r is atomic radius):

1. 20/3 πr3

2.  24/3 πr3

3.  12/3 πr3

4.  16/3 πr3

Subtopic:  Voids ,Radius Ratio & Coordination Number |
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Lithium borohydride (LiBH4), crystallises in an orthorhombic system with 4 molecules per unit cell. The unit cell dimensions are:- a = 6.81 Å , b = 4.43 Å ,c = 7.17 Å. If the molar mass of LiBH4 is
21.76 g mol-1.The density of the crystal is:-

1. 0.668 gcm-3
2. 0.585 gcm2
3. 1.23 gcm-3

4. None of these

Subtopic:  Density & Packing Fraction |
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The arrangement of Xions around A+ ion in solid AX is given in the figure (not drawn to scale).
If the radius of X is 250 pm,the radius of A+ is:
1. 104 pm

2. 125 pm

3. 183 pm

4. 57 pm

Subtopic:  Voids ,Radius Ratio & Coordination Number |
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In an f.c.c. unit cell. atoms are numbered as shown below.The atoms not touching each other are (Atom numbered 3 is face centre of front face).

1. 3&4

2. 1&3

3. 1&2

4. 2&4

Subtopic:  Introduction & Crystal System |
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A solid has a bcc structure. If the distance of closest approach between the two atoms is 1.73Å . The edge length of the cell is:

1. 200pm

2. 32 pm

3. 142.2 pm

4. 2pm

Subtopic:  Density & Packing Fraction |
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Which is covalent solid?

1. Silicate

2. Diamond

3. Graphite 

4. All of these

Subtopic:  Introduction & Crystal System |
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What type of crystal defects is indicated in the diagram given below?

1. Frenkel and Schottky defects

2. Schottky defect

3. Interstitial defect

4. Frenkel defect

Subtopic:  Imperfections in Solids |
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