Assertion : An important feature of Fluorite structures is that cations being large in size occupy FCC

lattice points whereas anions occupy all the tetrahedral voids giving the formula unit AB2(A: cation B: anion).

Reason : There are 6 cations and 12 anions per FCC unit cell of the Fluorite structure.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
  3. If the assertion is true but the reason is false
  4. If both the assertion and reason are false

Subtopic:  Voids, Radius Ratio & Coordination Number |
 51%
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NEET 2023 - Target Batch - Aryan Raj Singh
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Assertion : In NaCl crystal each Na ion is touching 6 Cl ions but these Cl ions do not touch each other.

Reason : The radius ratio roe rNa/rCl- is greater than 0.414, required for exact fitting.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
  3. If the assertion is true but the reason is false
  4. If both the assertion and reason are false
Subtopic:  Voids, Radius Ratio & Coordination Number |
 51%
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Assertion : The ratio of Zn2+ and F- per unit cell of ZnS and CaF2 is 1:2. 

Reason : In ZnS Zn2+ ions occupy alternate tetrahedral voids and in CaF2 F- ions occupy all the tetrahedral voids of FCC unit cell.

 

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
  3. If the assertion is true but the reason is false
  4. If both the assertion and reason are false
Subtopic:  Density & Packing Fraction |
 67%
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Sodium metal crystallizes in bcc lattice with cell edge =4.29 A0. The radius of sodium atom will be-

(1) 1.50 A0                                                 

(2) 1.86  A0

(3) 2.80 A0                                               

(4) None of these 

Subtopic:  Density & Packing Fraction |
 79%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh

The space lattice of graphite is

1. Cubic                                     

2. Tetragonal

3. Rhombic                                 

4. Hexagonal

Subtopic:  Introduction & Crystal System |
 70%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh

The edge length of the cube is 400pm. Its body diagonal would be-

(1) 500 pm                                         

(2) 693 pm

(3) 600 pm                                           

(4) 566pm

Subtopic:  Density & Packing Fraction |
 79%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh

A metallic element exists as a cubic lattice. Each edge of the unit cell is 2.88 A0. The density of the metal is 7.20 g cm-3. How many unit cell will be present in 100 g of the metal -

(1) 6.85×102                             

(2) 5.82×1023

(3) 4.37×105                             

(4) 2.12×106

Subtopic:  Density & Packing Fraction |
 68%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh

Iron crystallizes in a b.c.c. system with a lattice parameter of 2.861 A0. Calculate the density of iron in the b.c.c. system (Atomic weight of Fe = 56, NA=6.02×1023mol-1)

(1) 7.92g ml-1                                   

 

(2) 8.96g ml-1

(3) 2.78g ml-1                                     

(4) 6.72g ml-1

Subtopic:  Density & Packing Fraction |
 51%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh

An alloy of copper, silver, and gold is found to have copper constituting the ccp lattice. If silver atoms occupy the edge centers and gold is present at the body center, the alloy has a formula-

(1) Cu4Ag2Au                               

(2) Cu4Ag4Au

(3) Cu4Ag3Au                               

(4) CuAgAu

Subtopic:  Density & Packing Fraction |
 77%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh

Frenkel defect is not found in the halides of alkali metals because alkali metals have

1. high electropositivity

2. high ionic radii

3. high reactivity

4. ability to occupy interstitial sites

Subtopic:  Voids, Radius Ratio & Coordination Number |
 57%
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NEET 2023 - Target Batch - Aryan Raj Singh
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