ALCOHOL, PHENOLS AND ETHERS

SHAHEED RAJPAL DAV PUBLIC SCHOOL, DAYANAND VIHAR,DELHI 110092

CHEMISTRY

CLASS XII

TOPIC: ALCOHOL, PHENOLS AND ETHERS

1. Unlike phenols ,alcohols are easily protonated. Why?

2. Give chemical tests to distinguish between i) Phenol and Cyclohexanol and ii) Benzyl

alcohol & 2-Propanol, iii) Phenol & Benzoic acid , iv) sec & tert-butanol.

3. Propose a suitable mechanism for the preparation of ethoxyethane from ethanol.

4. Name the reagents which are used in following conversions:

i) 1°alcohol to an aldehyde, ii) butan-2-one to butan-2-ol, iii) phenol to 2,4,6-

tribromophenol.

5 .Why Me3COH is less acidic than Me3COH although carbon is more electronegative than

Si?

6 .Which one is more acidic : phenol or cresol? Why?

7. Predict the major product of acid-catalysed dehydration of : i) 1-methylcyclohexanol and

ii) butanol

8. Ortho and para nitrophenols are more acidic than phenol. Explain this observation with

the help of resonating structures of corresponding phenoxide ions.

9. Phenol is acidic yet it doesn’t react with sodium bicarbonate.Why?

10. Account for the following:

i) Methyl phenyl ether reacts with HI to give phenol & methyl iodide and not iodobenzene

and methyl alcohol

ii) Order of reactivity of HX towards the cleavage of ethers is: HI>HBr>HCl

iii) Alcohols are freely soluble in water while haloalkanes are not.

iv) Alcohols act as weak bases.

v) Phenol has a smaller dipole moment than methanol.

vi) Acidity of alcohols follows the order: 1°>2°>3°.

vii) Symmetrical ethers also possess a net dipole moment.

viii) Acid catalysed dehydration of t-butanol is faster than n-butanol.

ix) Sodium metal can be used for drying diethyl ether and benzene but not for an alcohol.

11. Describe the following :

i) Kolbe’s reaction

ii) Reamer Tiemann reaction

iii) Coupling reaction

iv) Schotten-Baumann reaction

v) Esterification

vii) Williamson’s synthesis

12.What happens when:

i) Ethanoyl chloride is treated with phenol

ii) Phenol is reacted with neutral FeCl3.

iii) Phenetole reacts with HI at 373K

iv) Diethyl ether reacts with Cl2 in dark.

13. The products of the reaction between Ethanol & H2SO4 depend upon the conditions

applied. Justify.

14. Conversions:

i) Benzene to cumene

ii) Phenol to p-hydroxyazobenzene

iii) Methanol to ethanol

iv) Ethanol to sodium ethoxide

v) Chlorobenzene to phenol

vi) Sodium propoxide to propoxypropane

vii) Ethylmagnesiumbromide to 1-propanol

viii) Propanol to 2-methyl-2-propanol

15. Describe the following processes with example:

i) Protonation , ii) acetylation

CHEMISTRY ASSIGNMENT: SOLUTIONS

SHAHEED RAJPAL DAV PUBLIC SCHOOL, DAYANAND VIHAR,DELHI 110092

CHEMISTRY

CLASS XII

TOPIC: SOLUTIONS

1. Raoult’s law is a special case of Henry’s law, comment. (1)

2. Why is a solution of ethylene glycol and water used as an antifreeze? (1)

3. Why is a bottle of ammonia cooled before opening the seal? (1)

4. In which of the following solvents will we get an abnormal molar mass for benzonic acid?

i) Water ii) Benzene . Give reason. (1)

5. What is the Van’t Hoff factor for – K4[Fe(CN)6] and K2SO4 (1)

6. Arrange the following one molal aqueous solutions in the increasing order of boiling points and

freezing points – glucose, sodium chloride, sodium phosphate, aluminium phosphate. (1)

7. Define vapour pressure of a liquid. What are the factors which influence the vapour pressure of

the liquid? (2)

8. Give reasons for the following observations: (1)

i) Salt is sprinkled on roads to clear the snow.

ii) A little salt is added to water while boiling eggs to avoid their breaking.

iii) Medicines are dissolved in 0.9% solution of NaCl before giving intravenous injections.

iv) Raw mangoes are placed in concentrated salt solution before making pickle.

v) Wilted flowers can come back to shape if placed in fresh water

vi) Saline gargles are suggested to soothe sore throat.

9. Explain the cause of non-ideal behaviours shown by a solution of (2)

ii) Acetone and chloroform

10. Boiling point of water increases by addition of common salt while the freezing point is lowered.

Represent this information graphically. (2)

11. Will the elevation in boiling point be same if 0.1 mole of sodium chloride or 0.1 mole

of sugar is dissolved in IL of water? Reason out your answer. (1)

12. Which colligative property is best suited to find the molar mass of a polymer? Give reason.(1)

13. A solution has 1:4 mole ratio for solute and solvent. The vapour pressure of solute and solvent are

440 and 120 mm of mercury respectively. The mole fraction of solute in the vapour phase will be:

a) 0.200 b) 0.549 c) 0.786 d) 0.478. (1)

Q.14 4% NaOH (W/V) and 6% urea solution (W/V) are equimolar but not isotonic. Why? (1)

Q.15 The vapour pressure of water at 25.0° C is 23.8 torr. Determine the mass of sodium chloride

needed to add to 400ml of water to change the vapour pressure to 2.8 torr. Assume the density

of water to be 1.0g/ml. (1)

Q.16 At the same temperature, Hydrogen is more soluble in water than Helium. Which of them

will have a higher value of KH and why? (2)

Q.17 Phenol associates in benzene to a certain extent to form dimer. A solution containing 2 x

10-2 kg of phenol in 1 kg of benzene has its freezing point decreased by 0.69K. Calculate

degree of association of phenol (If Kf for benzene is 5.12°K kg/ mol (3)

Q.18 At a given temperature the vapour pressure of pure liquid diethyl ether & isopropyl alcohol are

730 torr & 310 torr respectively. A solution prepared by mixing isopropyl alcohol & diethyl ether

obeys Raoult’s Law. At this temperature, what is the vapour pressure of diethyl ether over a

solution in which its mole fraction is 0.270? (2)

Q.19 Two sodium chloride solutions are separated by a semi permeable membrane. The concentration

of solution ‘A’ is 0.50 M and the concentration of solution ‘B’ is 0.250 M. Over time, there will

be a measurable movement of (1)

(a) Water from solution A to B. (b) Water from solution B to A.

(c) Sodium chloride from solution B to A (d) Sodium chloride from solution A to B

(e) two of these are correct.

Q.20 On the basis of the given observation in each case predict (a) whether i=1 ,i<1or i>1

 (b) comment on the molecular state of the solute whether normal, association or

 (i) ∆Tb : expected 0.82 K, observed 0.82 K

 (ii) π: expected 1.8 bar , observed 2.1 bar

 (iii) ∆Tf: expected 1.68K, observed 1.42 K (3)

Q.21 Of the following compounds, which are likely to increase in solubility as the temperature of the

(a) Glucose, C6H12O6 (b) CO2 (c) NaBr (d) CuSO4 (e) CH4

Q.22 A nurse prepared three injections of concentration 1.0%, 0.75% and 0.9% saline to be injected

intravenously to a patient. Which is the most suitable concentration to be used? Why? (2)

CHEMISTRY ASSIGNMENT: AMINES

WORKSHEET

CLASS XII – CHEMISTRY

AMINES

1. Arrange the following in increasing order of basic strength: a) C2H5NH2,C6H5NH2,NH3,C6H5CH2NH2,(C2H5)2NH

b) C2H5NH2,(C2H5)2NH,(C2H5)3N,C6H5NH2

c) CH3NH2,(CH3)2NH,(CH3)3N,C6H5NH2,C6H5CH2NH2

2. Write the chemical reaction of aniline with benzoyl chloride and write the name of the product.

3. Give one chemical test to distinguish between the following pairs of compounds: a) Methylamine and dimethylamine b) Ethylamine and aniline c) Aniline and benzylamine d) Secondary and tertiary amines e) Aniline and N-methylaniline

4. Account for the following: a) pKb of aniline is more than that of methylamine b) Ethylamine is soluble in water,whereas aniline is not. c) Although amino group is o- and p- directing in aromatic electrophilic substitution reactions ,aniline on nitration gives a substantial amount of mNitroaniline. d) Aniline does not undergo Friedel-Crafts reaction. e) Diazonium salts of aromatic amines are more stable than those of aliphatic amines. f) Gabriel Phthalimide synthesis is preferred for synthesising primary amines.

5. Distinguish between primary, secondary and tertiary amines.

6. Write short notes on the following: a) Carbylamine reaction b) Diazotisation c) Hoffmann’s bromamide reaction d) Ammonolysis e) Gabriel Phthalimide synthesis f) Coupling reaction

7. Give an example of a Zwitter ion.

8. Explain why an alkylamine is more basic than ammonia.

9. How can you convert an amide into an amine having one carbon atom less than the starting compound? Name the reaction

10. What is the role of pyridine in the acylation reaction of amines?

CHEMISTRY ASSIGNMENT: POLYMERS

Chapter : 15.

POLYMERS

Level-1:Questions

1) What are polymers?

A: These are referred to as Macromolecules which are formed by joining of repeating structural units on a large scale.

 2) Give two examples each of natural and of synthetic polymers.

A: Natural polymers e.g.:- proteins, starch Synthetic polymers e.g.:- Polythene, Nylon-6,6

3) What are biodegradeable polymers? Give one example.

 A: Polymers which are degraded easily by environmental processes. e.g.: PHBV

4) How are the polymer classified on the basis of structure?

A: They are three types based on the structure of polymers a) Linear polymers b) branched polymers c) cross linked polymers.

 5) Define the term ‘polymerisation’.

A: The process of making polymer from monomers.

6) What are the monomers for the following polymers: i) Polythene ii) PVC iii) Teflon iv) Polystyrene

A: i) Ethene ii) Vinyl chloride iii) Tetrafluoroethene iv)Styrene

7) In which classes, the polymers are classified on the basis of molecular forces?

 A: Elastomers, Fibres, thermoplastic and thermosetting polymers

8) Give an example of elastomer.

 A: Neoprene

 9) Identify the polymer. -A-A-A-A-AA:

 Homopolymer

 10)Define the term ” homopolymerisation”.

 A: The process of making polymer by adding one kind of monomers

11) Identify the polymer. -A-B-A-B-A-B-A-BA:

 Copolymer

12) Why rubbers are called “Elastomers”?

A: They can be stretched and retract to its original position after the release of force.