Chemistry Question Bank

For tetrahedral coordination the radius ratio r r should be

The ratio of cationic radius to anionic radius in an ionic crystal is greater than 0.732. Its coordination number is

For a solid with the following structure, the co- ordination number of the point B is

An ionic compound has a unit cell consisting of A ions at the corners of a cube and B ions on the centres of the faces of the cube. The empirical formula for this compounds would be

Aluminium has fcc structure. The length of the unit cell is 404 pm. If the density of the metal is 2.7 g cm–3, the molar mass of Al atom is

Ag forms ccp lattice and X-ray studies show that the edge length of its unit cell is 408.6 pm. Find the density of silver. (Given that atomic mass of silver = 107.9 u)

An element with atomic mass 100 has a bcc structrue and edge length 400 pm. The density of element is

How many lithium atoms are present in a unit cell with edge length 3.5 Å and density 0.53 gcm –3? (Atomic mass of Li = 6.94)

The unit cell of aluminium is a cube with an edge length of 405 pm. The density of aluminium is 2.70 g cm –3. What is the structure of unit cell of aluminium?

Which of the following has the highest value of energy gap?

Assertion : In Schottky defects, electrical neutrality is maintained. Reason : Equal number of cation and anion vacancies are present.

Assertion : Unlike Schottky defects, Frenkel defects don’t change the density of solids. Reason : These defects are basically point defects.

Assertion : Co-ordination number of rock salt is 8. Reason : Limiting radius ratio for rock salt is between 0.414 and 0.732.

Assertion : Packing in body centered cubic (bcc) structure is more efficient than in cubic closed packed (ccp) structure. Reason : 74% of the total space is occupied by the atoms in fcc structure while only 68% of the…

Assertion : Covalent crystals have a higher melting point. Reason : Covalent bonds are stronger than ionic bonds.

Assertion : Crystalline solids are anisotropic. Reason : The constituent particles are very closely packed.

Assertion : The window glass of the old buildings is thick at bottom. Reason : Glass is a supercooled liquid of high viscosity and has the property to flow.

Assertion : Glass is an amorphous solid. Reason : In glass, there is only short range order.

Which type of 'defect' has the presence of cations in the interstitial sites ?

A particular solid is very hard and has a high melting point. In solid state, it is a non-conductor and its melt is a conductor of electricity. Classify the solid.

Copper crystallises in fcc lattice with a unit cell edge of 361 pm. The radius of copper atom is

Percentage of free space in cubic close packed structure and in body centred packed structure are respectively

The density of KBr is 2.75 g cm –3. The length of the unit cell is 654 pm. Atomic mass of K = 39, Br = 80. Then the solid is

Density of NaCl crystal assuming all sites are occupied = 2.178 × 103 kg m–3

A sample of electrically neutral NaCl crystal is analysed for its density which has some unoccupied sites. Two readings where taken.