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Chemistry XIIC

Mr.N.V.Jyothi Mohan, PGT (Chem)

Date of submission: 01/06/2011

 

Chapter:Solid State

1. Give an example of a ‘covalent solid’.

2. Which ionic crystal shows both ‘schottky’ and ‘frenkel’ defect ?

3. What is anisotropy?

4. What are the co-ordination numbers of the cation and anion present in ‘NaCl type’ crystals?

5. Which type of semi conductor can act as a ‘rectifier’ ?

6. How molality varies with temperature and why?

7. Calculate the value of the Avagadro constant from the following data- Density of NaCl= 2.165 g/cm3, distance between Na+ and Cl in NaCl is 281pm and molar mass of NaCl is 58.5 gm/mol.

8. If NaCl is doped with 10-3 mol % of SrCl2, what is the concentration of cation vacancies?

9. What is F centre? Give an example of a crystal with F centre.

10. What is an extrinsic semiconductor? How the conductivity of a semi conductor can be increased without increasing the temperature?

11. Explain ferro, ferri and anti ferro magnetism with examples.

12. An element with 60.23 amu atomic mass crystallises in bcc lattice.It has a density of 10 g/cm3 at room temperature. Calculate the atomic radius of the element.

 

Chapter: Solutions

1. Calculate the mole fractions of the solute and solvant in a 10 % (by mass) solution of Sodium Carbonate in water.

2. If density of lake water is 1.25 g/mland it contains 92.0 gm of Na+ions per kgm of water. Calculate the molarity and molality of Na+ ions in lake.

3. Why different liquids have different vapor pressure?

4. Explain Henry’s law and write two of its applications.

5. Write the mathematical expressions of Raoult’s law for volatile and nonvolatile solutes.

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