Prepare for AISSCE (CBSE Class XII) Chemistry through selected Long Answer Type Questions – Unit 2 – Solutions
AISSCE (CBSE Class XII) Chemistry through selected Long Answer Type Questions –
Unit 2 – Solutions
- What do you understand by vapour pressure of a liquid? How does it vary with temperature? Using pressure temperature curve show that what is normal boiling point and standard boiling point of a liquid?
- What is Vant Hoff’s factor? How is it related to degree of dissociation of the electrolyte in the solution? What is its value when the solute undergoes association?
Prepare for AISSCE (CBSE Class XII) Chemistry through selected Long ANswer Type Questions – Unit 1 – The Solid State
Chapterwise long answer type questions for AISSCE (CBSE Class XII) Chemistry
Unit 1 – The Solid State
- Describe the following
- Hexagonal close packing
- Cubic close packing
- Body centred cubic packing
- What are the seven types of crystal systems? Give their unit cell dimensions. Draw structures of different types of unit cells which are possible for cubic crystal system.
- What do you mean by stoichiometric point defects? Describe briefly the various types of stoichiometric point defects.
- Explain the following.
- Schottky defect
- Frenkel defect
- F – centres
- Explain the conduction behaviour of metals, semiconductors and insulators on the basis of band theory of solids. What is the effect of increase of temperature on electrical conductivity of metals, semiconductors and insulators.
- Explain the following with suitable examples
- Paramagnetic substances
- ferrimagnetic substances
- Ferromagnetic substances
MM : 25 TIME : 40 MIN.
1. Give an example of ionic compound which show Frenkel defect.
2. What type of semiconductor is obtained when silicon is doped with Arsenic?
3. How do metallic and ionic substances differ in conducting electricity ?
4. How are the following properties of the crystals affected by Schottky and Frenkel defects
(i) Density (ii) Electrical Conductivity
5. What is the number of atom in a unit cell of
(i) face centered cubic structure
(ii) body centered cubic structure
6. What are F – centers ? Why are solids containing F – centers paramagnetic?
7. Account for the following :
(i) Fe3O4 is a ferromagnetic at room temperature but becomes paramagnetic at 850 K.
(ii) Zinc oxide on heating becomes yellow.
(iii) Frenkel defect does not change the density of AgCl crystal .
8. Chromium metal crystallizes in a body centered cubic lattice . The length of the unit cell edge is found to be 287 pm . Calculate the atomic radius of chromium
9. The density of Cu metal is 8.95 g cm-3. If the radius of Cu atom is 127.8 pm . Is the copper unit cell a simple cubic , a body centered or a face centered cubic structure ?
10. A cubic solid is made of two elements X and Y . Atoms Y are at corner of the cube and X at body centre . What is the formula of the compound ?
11. Calculate the distance between Na+ and Cl- ion in NaCl crystal if its density is 2.165 g cm-3 (Molar mass on NaCl = 58.5 g mol-1 )
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