MM : 25 TIME : 45min.
1. Write a chemical equation each to illustrate the following reaction:
(a) Carbylamine reaction
(b) Hofmann – bromamide reaction
(c) Gabriel phthalimide synthesis
(d) Balz – Schiemann reaction
(e) Diazotisation reaction
2. Separate primary secondary and tertiary amines on the basis of Hinsberg’s method.
3. Convert the following :
(a) Aniline into fluorobenzene
(b) Toluene into p-toluic acid.
(c) Aniline to sulphanilic acid .
4. Why are amines are less acidic than alcohols of comparable molecular masses?
5. How is basic strength of aromatic amines affected by the presence of electron releasing group on the benzene ring?
6. Explain why Amino group in ethylamine is basic but not in acetamide ?
7. Out of aliphatic and aromatic amines which one is soluble in water and why?
8. Give one chemical test to distinguish between benzyl amine and anilne.
9. What happens when ethylamine is treated with CHCl3 in the presence of ethanolic KOH.
10. Discuss the importance of pH in coupling reaction.
MM : 25 TIME : 40 MIN.
1. Two liquids A and B boil at 145oC respectively and 190oc respectively . Which of them has a higher vapour pressure at 80oc ?
2. Why is freezing point depression of 0.1 M sodium chloride solution nearly twice that of 0.1M glucose solution ?
3. Define the term molarity of the solution . State one disadvantage in using the molarity as the unit of concentration.
4. Define the term osmotic pressure . What is advantage of using osmotic pressure as compared to other colligative properties for the determination of molar masses of solutes in the solutions ?.
5. Non – ideal solutions exhibit either positive or negative deviation for Raoult’s law . What are these deviations and why are they caused ?
6. What mass of ethylene glycol (molar mass = 62g mol-1) must be added to 5.50 Kg of water to lower the freezing point of water to lower the freezing point of water from 00c to – 10 .0 0c ? [Kf for water = 1.86 K Kg mol-1 )
7. What concentration of nitrogen should be present in a glass of water at room temperature. Assume a temperature of 25oc a total pressure of 1 atmosphere and mole fraction of nitrogen in air of 0.78 (Kh for N2 = 8.42 x 10-7 M/mm Hg) .
8. The boiling point elevation of 0.30 g acetic acid in 100 g benzene is 0.0633 K . Calculate the molar mass of acetic acid from this data . What conclusion can you draw about the molecular state of the solute in the solution ? [Kb = 2.53 K Kg mol-1)
9. An antifreeze solution is prepared from 222.6 g of ethyleneglycol and 200 g of water . Calculate the molality of the solution . If density of this solution be 1.072gml-1 What will be the molarity of the solution?
10. Urea forms an ideal solution in water . Determine the vapour pressure of an aqueous solution containing 10% by mass of urea at 400c ( vapour pressure of water = 55.3 mm of Hg)
11. A 4% solution of sucrose is isotonic with 3% solution of an unknown organic substance . Calculate the molecular mass of unknown substance .
CBSE Chemistry Question Bank for Class 12
The solid State
Very Short Answer type Questions
- Why are solids rigid?
- Name two types in which solids are broadly classified.
- Give one example each for a crystalline and amorphous solid.
- How many atoms per unit cell are present in (i) hcp (ii) fcc (iii) bcc
- How many tetrahedral holes are present per unit cell in an (1)hcp structure and (2) fcc structure?
- What type of coordination would you expect when (1)all the tetrahedral holes in an fcc structure of anions are occupied by cations, (2) half of the tetrahedral holes in an fcc structure of anions are occupied by cations and (3) all the octahedral holes of an fcc structure
- List two difference between acid and base on the basis of chemical properties
- Using the quation for electrolytic decomposition of water differentiate between a skeletal chemical equation and a balanced chemical equation
- State the change in colour name of the compound when iron material is exposed to air
With the help of chemical equation for the reaction describe the method of obtaining copper from sulphide ore