# In corundum, oxide ions are arranged in hcp arrangement and the aluminium ions occupy two-third of the octahedral holes. Its formula is:

1.  Al2O4

2.  Al2O3

3.  Al3O4

4.  AlO2

4

Al2O3

Explanation :
No Explanation available for this question

# Total volume of atoms present in face centred cubic unit cell of metal is (r is atomic radius)

1.  24/3 πr3

2.  12/3 πr3

3.  16/3 πr3

4.  20/3 πr3

4

16/3 πr3

Explanation :
No Explanation available for this question

# Which one has highest melting point

1.  Ionic crystal

2.  Molecular crystal

3.  Covalent crystal

4.  Metallic crystal

4

Ionic crystal

Explanation :
No Explanation available for this question

# The Bragg equation giving relationship between distance between the planes of constituent particles in the crystal (d),angle of diffracted X-ray beam (2θ) and wavelength of X-ray (λ) used is :(where 'n' stands for serial order of diffracted beam )

1.  d=nλsinθ

2.  λd=(2sinθ) /n

3.  λ=(2dsinθ) /n

4.  nλ=dsin2θ

4

λ=(2dsinθ) /n

Explanation :
No Explanation available for this question

# For tetrahedral coordination, the radius ratio, r+/r- is:

1.  0.224 - 0.414

2.  0.414 - 0.526

3.  0.414 - 0.732

4.  0.732 - 1.0

4

0.414 - 0.526

Explanation :
No Explanation available for this question

# The most unsymmetrical crystal system is :

1.  Cubic

2.  Hexagonal

3.  Triclinic

4.  Orthorhombic

4

Triclinic

Explanation :
No Explanation available for this question

# The number of NaCl formula units in a unit cell of sodium chloride is

1.  1

2.  2

3.  4

4.  8

4

4

Explanation :
No Explanation available for this question

# which of the following is ferrite

1.  Na2Fe2O4

2.  MgFe2O4

3.  AlFe2O4

4.  Zn3FeO4

4

MgFe2O4

Explanation :
No Explanation available for this question

# Body centred cubic lattice has coordination number

1.  6

2.  8

3.  10

4.  12

4

8

Explanation :
No Explanation available for this question

1.  Triclinic

2.  Rhombohedral

3.  Tetragonal

4.  Isomorphous

4