Given below are the Solid State Class 12 Important Questions

a. Concepts questions

b. Calculation problems

c. Short Answer

d. Cubic cell problems

a. Concepts questions

b. Calculation problems

c. Short Answer

d. Cubic cell problems

A compound is formed by 2 elements M & N. N forms ccp and atoms of M occupy 1/3rd of tetrahedral voids. What is the formula of the compound?

An element with molar mass $2.7 \times 10^{-2}$ Kg/mol. forms a cubic units cell with edge length of 405 p. m. If the density is $2.7 \times 10^3 \ Kg/m^3$. Find the nature of a cubic unit cell.

Solution

Gold (Atomic Radius = 0.144 nm) crystallizes in FCC. Find the length of the side of the cell.

Solution

Alluminium crystallizes in cubic close-packed structure. it's metallic radius is 125 pico meter.

(i) Find the length of the side of the unit cell.

(ii) How many unit cells are present in 1 cm

Solution

Non-stoichiometric cuprous oxide,($Cu_2O%) can be prepared in laboratory. In this oxide Cu to O ratio is slightly less than 2 : 1. Can you account for the fact that this substance is a P – type semi – conductor?

Solution

What type of stoichimetric defect is shown by

(i) ZnS

(ii) AgBr

Solution

Ionic solids are hard and brittle. Why?

Solution

Classify each of the following as either a P – type or N – type semi – conductor

(i) Germanium doped with indium

(ii) Boron doped with silicon

Solution

A metal crystallizes into two cubic system-face centred cubic (fcc) and body centred cubic (bcc) whose unit cell lengths are 3.5 and 3.0 Å respectively. Calculate the ratio of densities of fcc and bcc.

Solution

Niobium crystallises in body-centred cubic structure. If the atomic radius is 143.1 pm, calculate the density of Niobium. (Atomic mass = 93u).

Solution

(i)If the radius of the octahedral void is 'r' and radius of the atoms in close packing is 'R'. What is the relation between 'r' and 'R'

(ii) Tungsten crystallizes in body centred cubic unit cell. If the edge of the unit cell is 316.5 pm. What is the radius of tungsten atom?

Solution

(i)A metal crystallizes in a body centred cubic structure. If ‘a’ is the edge length of its unit cell, ‘r’ is the radius of the sphere. What is the relationship between 'r' and 'a'?

(ii) An element with molar mass 63 g / mol forms a cubic unit cell with edge length of 360.8 pm. If its density is 8.92 g/ cm

What is the nature of the cubic unit cell?

Solution

An element crystallizes in a f.c.c. lattice with cell edge of 250 pm. Calculate thedensity if 300 g of this element contain $2 \times 10^{24}$ atoms.

For Fe , a=286 pm, Density = 7.86 g/cm

(i) Find the nature of a cubic unit cell.

(ii) Calculate the Radius of Iron

Solution

Tungsten has Density of 19.35 g/cm

Solution

A metallic element has a BCC lattice. Each edge of the unit cell is 288 pm. The density of the metal is 7.2 g/cm

Ans $1.158 \times 10^{24}$ atoms

With the help of a labelled diagram show that there are four octahedral voids per unit cell in a cubic close packed structure.

Show that in a cubic close packed structure, eight tetrahedral voids are present per unit cell