Solid States

Structure of a mixed oxide is ccp. Cubic unit cell of mixed oxide is composed of oxide ions.

One Fourth of tetrahedral voids are occupied by divalent metal A and all the octahedral voids

are occupied by monovalent metal B. Formula of oxide is.

• A₂B₃O₄

• AB₂O₂

• ABO₂

• A₂BO₂

In face centred cubic lattice, A occupies corners and B occupies face centres. If one atoms of

B is missing from one of the face centre, formula of the compound is.

• AB₂

• A₂B₂

• A₂B₅

• A₂B

No. of tetrahedral voids in the unit cell of a face centred cubic lattice of similar atoms is.

• 4

• 6

• 8

• 12

The number of atoms in 100 g of a face crystal with density = 10 g/cm and cell edge equal to

200 pm is equal to.

• 5x10²⁴

• 5x10²⁵

• 6x10²³

• 2x10²⁵

Percentages of free space in cubic close packed structure and in body centred packed

structure are respectively.

• 48% and 36 %

• 32% and 48 %

• 30% and 26 %

• 26% and 32 %

Copper crystallizes in fcc with a unit cell length of 361 pm. What is the radius of copper

atom?

• 108 pm

• 127 pm

• 157 pm

• 181 pm

Schottky defect in crystals is observed

• when unequal number of cations and anions are missing from the lattice.

• when equal number of cations and anions are missing from the lattice.

• when an ion leaves its normal site and occupies an interstitial site.

• when the density of the crystal is increased.

The colours of some otherwise colourless compounds are due to.

• Metal deficiency defect

• Schottky defect

• Frenkel defect

• Metal excess defect (F-Centres)

Crystal with metal deficiency defect is.

• FeO

• NaCl

• ZnO

• KCl

Which among the following is not an example of amorphous solids?

• Quartz

• Glass

• Coke

• Plastic