1. An alcohol A (C4H10O) on
oxidation with acidified potassium dichromategives carboxylic acid B (C4H8O2).
Compound A when dehydrated withconc. H2SO4 at 443 K
gives compound C. Treatment of C with aqueousH2SO4 gives compound
D (C4H10O) which
is an isomer of A. CompoundD is resistant to oxidation but compound A can be
easily oxidised. Identify
A, B, C and D and
write their structures.
2. An organic
compound A having molecular formula C6H6O gives
acharacteristic colour with aqueous FeCl3. When A
is treated with NaOHand CO2 at 400 K under pressure, compound B is
obtained. CompoundB 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 andD. What is the common
name of Drug D?
3. An ether A (C5H12O) when
heated with excess of hot concentrated HIproduced 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.
4. Phenol, C6H5OH when it
first reacts with concentrated sulphuric acid, formsY.Y is reacted with
concentrated nitric acid to form Z. Identify Y and Z andexplain why phenol is
not converted commercially to Z by reacting it withconc. HNO3.
5. Give reason for
the following:
(i) The C–O–C bond
angle in dimethyl ether is (111.7°)
(ii) Alcohols have
higher boiling points than ethers of comparablemolecular masses.
(iii) Phenols are
more acidic than alcohols.
(iv) Nitro phenol is
more acidic than o-methoxyphenol.
(v) Phenol is more
reactive towards electrophilic substitution reactionthan benzene.
(vi) The following is
not an appropriate method for the preparation of1-methoxy-4-nitrobenzene;
(vii) Write the
suitable reaction for the preparation of1–methoxy–4–nitrobenzene
(viii) o-nitrophenol
is steam volatile but p-nitrophenol is not.
(ix) phenol is less
polar than ethanol.
(x) The phenyl methyl
ether reacts with HI fo form phenol and
iodomethane and not
iodobenzene and methanol.
(xi) methanol is less
acidic than water.
(xii) alcohols can
act as weak base as well as weak acids.
(xiii) phenols do not
give protonation reaction readily.
(xiv) absolute
ethanol can not be obtained by factional distillation of ethanoland water
mixture.
6. Arrange the
following in the increasing order of property shown :
(i) methanol,
ethanol, diethylether, ethyleneglycol. (Boiling points)
(ii) phenol,
o-nitrophenol, m-nitrophenol, p-nitrophenol. (Acid strength)
(iii) dimethylether,
ethanol, phenol. (Solubility in water)
(iv) n-butanol,
2-methylpropan-1-ol, 2-methylpropan-2-ol. (Acid strength)
7. Give a chemical
test to distinguish between the following pair of compounds.
(i) n-propyl alcohol
and isopropylalcohol
(ii) methanol and
ethanol
(iii) cyclohexanol
and phenol.
(iv) propan-2-ol and
2-methylpropan-2-ol.
(v) phenol and
anisole
(vi) ethanol and
diethyl ether
8. An organic
compound (A) having molecular formula C3H7Cl on
reactionwith alcoholic solution of KCN gives compound B. The compound B onhydrolysis
with dilute HCl gives compound C. C on reduction withH2/ Ni gives
1-aminobutane. Identify A, B and C.
An optically active
compound having molecular formula C7H15Br
reactswith aqueous KOH to give C7H15OH, which
is optically inactive. Givemechanism for the reaction.A racemic mixture is
obtained which is optically inactive.
9. An organic
compound C8H9Br has
three isomers A, B and C. A is opticallyactive. Both A and B gave the white
precipitate when warmed with alcoholicAgNO3 solution
in alkaline medium. Benzoic acid, terephthalic and pbromobenzoicacid were
obtained on oxidation of A, B and C respectively.Identify A, B and C.
10. An alkyl halide X
having molecular formula C6H13Cl on
treatment withpotassium tert-butoxide gives two isomeric alkenes Y and Z but
alkene yis symetrical. Both alkenes on hydrogenation give 2, 3-dimethylbutane.
Identify X, Y and Z.
11.Give reasons for
the following :
(i) The bond length
of C–Cl bond is larger in haloalkanes than that inhaloarenes.
(ii) Although alkyl
halides are polar in nature but are not soluble inwater.
(iii) tert-butyl
bromide has lower boiling point than n-Butyl bromide.
(iv) haloalkanes
react with KCN to form alkyl cyanide as main productwhile with AgCN alkyl
isocyanide is the main product.
(v) sulphuric acid is
not used in the reaction of alcohol with Kl.
(vi) thionyl chloride
is the preferred reagent for converting ethanol tochloroethane.
(vii) haloalkanes
undergo nucleophilic substitution reaction easily buthaloarenes do not undergo
nucleophilic substitution under ordinaryconditions.
(viii) chlorobenzene
on reaction with fuming sulphuric acid gives orthoand para chlorosulphonic
acids.
(ix) 2, 4-dinitro
chlorobenzene is much more reactive than chlorobenzenetowards hydrolysis
reaction with NaOH.
(x) Grignard reagent
should be prepared under anhydrous conditions.
(xi) the dipole
moment of chlorobenzene is lower than that of cyclohexylchloride.
(xii) neopentyl
bromide undergoes nucleophilic substitution reactions veryslowly
(xiii) vinyl chloride
is unreactive in nucleophilic substitution reaction.
(xiv) An optically
inactive product isobtained after the hydrolysis ofoptically active 2-
bromobutane.
12.Arrange the
following in the increasing order of properly indicated :
(i) bromomethane,
chloromethane, dichloromethane. (Increasing order
of boiling points).
(ii) 1-chloropropane,
isopropyl chloride, 1-chlorobutane (Increasing order
of boiling point)
(iii)
dichloromethane, chloroform, carbon terachloride. (Increasing order
of dipole moment.
(iv) CH3F, CH3Cl, CH3Br, CH3l
(Increasing reactivity towards nucleophilic
substitution and
increasing order of dipole moment)
(v) o,m.p-dichlorobenzenes
(Increasing order of melting points).
13.Arrange the
following in the increasing order of properly indicated :
(i) bromomethane,
chloromethane, dichloromethane. (Increasing orderof boiling points).
(ii) 1-chloropropane,
isopropyl chloride, 1-chlorobutane (Increasing orderof boiling point)
(iii)
dichloromethane, chloroform, carbon terachloride. (Increasing orderof dipole moment.
(iv) CH3F, CH3Cl, CH3Br, CH3l
(Increasing reactivity towards nucleophilicsubstitution and increasing order of
dipole moment)
(v) o,m.p-dichlorobenzenes
(Increasing order of melting points).
14. How will you
bring about the following conversions?
(i) benzene to
3-bromonitrobenzene
(ii) ethanol to
but-1-yne
(iii) 1-bromopropane
to 2-bromopropane
(iv) benzene to
4-bromo-1-nitrobenzene
(v) aniline to
chlorobenzene
(vi)
2-methyl-1-propene to 2-chloro-2-methylpropane
(vii) ethyl chloride
to propanoic acid
(viii) but-1-ene to
n-butyl iodide
(ix) benzene to
phenylchloromethane.
(x) tert-butyl
bromide to isobutyl bromide.
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