ASSIGNMENT-4
Class 12 Chemistry
Chapter-11 (Alcohols, Phenols and Ethers)
1. Write the structures of the compounds whose names are given below:
i. 3, 5-dimethoxyhexane-1, 3, 5-triol
ii. cyclohexylmethanol
iii. 2-ethoxy-3-methylpentane
iv. 3-chloromethylpentan-2-ol
v. p-nitroanisole
.
2. Complete the following reactions :
i.
ii.
iii.
iv.
v.
vi.
vii. CH3CH2CH2O - CH3+HBr →
viii. (CH3)3C - O - C2H5 + HI →
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ix.
x.
xi.
xii.
3. What happens when:
i. aluminium reacts with tert-butyl alcohol
ii. phenol is oxidised with chromic acid
iii. cumene is oxidised in the presence of air and the product formed is treated with
dilute acid.
iv. phenol is treated with conc. HNO3 .
4 Identify the missing reactant or product A to D in the following equations:
i.
ii.
iii.
iv. CH3OC6H5 + HI → (D)
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5 Identify X, Y and Z in the following sequence of reactions:
1.
2.
3.
6 Give reasons for the following:
a The C–O–C bond angle in dimethyl ether is (111.7°)
b. Alcohols have higher boiling points than ethers of comparable molecular masses.
c. Phenols are more acidic than alcohols.
d. Nitrophenol is more acidic than o-methoxyphenol.
e.Phenol is more reactive towards electrophilic substitution reaction than benzene.
f.The following is not an appropriate method for the preparation of t-butyl ethyl ether:
* What would be the major product of this reaction?
* Write suitable reaction for the preparation of t–butyl ethyl ether.
g.phenol is less polar than ethanol.
h.The phenyl methyl ether reacts with HI fo form phenol and iodomethane and not
iodobenzene and methnol.
7.Arrange the following in the increasing order of property shown:
a. methanol, ethanol, diethylether, ethyleneglycol. (Boiling points)
b. phenol, o-nitrophenol, m-nitrophenol, p-nitrophenol. (Acid strength)
c. dimethylether, ethanol, phenol. (Solubility in water)
d. n-butanol, 2-methylpropan-1-ol, 2-methylpropan-2-ol. (Acid strength)
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8.Give a chemical test to distinguish between the following pair of compounds.
a. n-propyl alcohol and isopropylalcohol
b. methanol and ethanol
c. cyclohexanol and phenol.
d. propan-2-ol and 2-methylpropan-2-ol.
e. phenol and anisole
9. An alcohol A (C4H10O) on oxidation with acidified potassium dichromate gives carboxylic
acid B (C4H8O2). Compound A when dehydrated with conc. H 2SO4 at 443 K gives
compound C. Treatment of C with aqueous H 2SO4 gives compound D (C4H10O) which is
an isomer of A. Compound D is resistant to oxidation but compound A can be easily
oxidised. Identify A, B, C and D and write their structures.
10. An organic compound A having molecular formula C6H6O gives a characteristic colour
with aqueous FeCl3. When A is treated with NaOH and CO2 at 400 K under pressure,
compound B is obtained. Compound B on acidification gives compound C which reacts
with acetyl chloride to form D which is a popular pain killer. Deduce the structure of A, B,
C and D. What is the common name of Drug D?
11.An ether A (C5H12O) when heated with excess of hot concentrated HI produced two
alkyl halides which on hydrolysis from compounds B and C. Oxidation of B gives an acid D
whereas oxidation of C gave a ketone E. Deduce the structures of A, B, C, D and E.
12.Phenol, C6H5 OH when it first reacts with concentrated sulphuric acid, forms Y.Y is
reacted with concentrated nitric acid to form Z. Identify Y and Z and explain why phenol is
not converted commercially to Z by reacting it with conc. HNO3.
13 Synthesise the following alcohols from suitable alkenes.
a.
b.
14 How are the following ethers prepared by Williamson synthesis?
a. Ethoxybenzene
b. 2–methoxy–2–methylpropane
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