CBSE Questions for Class 11 Medical Chemistry Hydrocarbons Quiz 5 - MCQExams.com

$$CH_3-\overset{CH_3}{\overset{|}{C}H}-CH_3$$(excess)+$$Br_2\xrightarrow{hv} CH_3-\overset{CH_3\!\!\!\!}{\overset{|}{\underset{Br\!\!}{\underset{|}C}}}-CH_3+CH_3-\overset{CH_3}{\overset{|}{C}H}-CH_2-Br$$

The relative reactivity of $$1^oH, 2^oH$$ and $$3^oH$$ in bromination reaction has been found to be 1:82:1600 respectively. In the reaction the percentage yields of the products (A) and (B) are expected to be
  • 99.4%, 0.6%
  • 50%, 50%
  • 0.6%, 99.4%
  • 80%, 20%
2-Bromo-3-phenylpropane can be synthesized by:
  • $$C_6H_5CH_2CH(OH)CH_3+PBr_3 \rightarrow $$
  • $$C_6H_5CH=CHCH_3+HBr+ benzoyl peroxide\rightarrow $$
  • $$C_6H_5CH_2CH_2CH_3+Br_2+ light\rightarrow $$
  • none of these
Select true statement(s):
  • Stereochemical outcome of a radical substitution and a radical addition reaction is identical.
  • I2 does not react with ethane at room temperature even though I2 is more easily cleaved homolytically

    than the other halogens.
  • The rate of bromination of methane is decreased if HBr is added to the reaction mixture.
  • Allylic chloride adds halogens faster than the corresponding vinylic chloride.
An optically active hydrocarbon(X) on catalytic hydrogenation gives an optically inactive compound (Y), C$$_6$$H$$_{14}$$. The hydrocarbon (X) is-
  • 3-methyl-1-pentene
  • 3-methyl-2-pentene
  • 2-ethyl-1-butene
  • 3-methylcyclopentene
Name of the compund given below is :-

275166.png
  • 2,3-Diethyl heptane
  • 5-Ethyl-6-methyl octane
  • 4-Ethyl-3-methyl octane
  • 3-Methyl-4-ethyl octane
The incorrect IUPAC name is:
The correct IUPAC name of the given compound is:
274444.png
  • $$2-ethyl-3-methylpentane$$
  • $$3,4-dimethylhexane$$
  • $$2-Sec-butyl$$ $$butane$$
  • $$2,3-dimethyl$$ $$butane$$

The IUPAC name of the compound is:
275527_078a1bedafb3481ba461595a9aa0b895.png
  • 2, 3-Dimethyl hexane
  • 2-Ethyl-4-methyl pentane
  • 3-Ethyl-2-methyl pentane
  • 2, 4-Dimethyl hexane
Which of the following compounds represents 2,2,3-trimethyl hexane ?
  • $$CH_{3}C(CH_{3})_{2}CH_{2}CH_{2}CH(CH_{3})_{2}$$
  • $$CH_{3}C(CH_{3})_{2}CH_{2}CH(CH)CH_{2}CH_{3}$$
  • $$CH_{3}C(CH_{3})_{2}CH(CH_{3})CH_{2}CH_{2}CH_{3}$$
  • $$CH_{3}C(CH_{3})_{2}CH_{2}C(CH_{3})_{2}CH_{3}$$
Which of the following halogen reacts with alkanes with explosive violence?
  • $$F_2$$
  • $$Cl_2$$
  • $$Br_2$$
  • $$l_2$$
Which alkane will give only one monochlorinated product?
  • $$CH_3CH_2CH_3$$
  • $$CH_3CH_2CH_2CH_3$$
  • $$(CH_3)_4C$$
  • $$CH_3(CH_2)_3CH_3$$
On heating sodium propionate with sodalime the hydrocarbon obtained is:
  • butane
  • ethane
  • propane
  • ethene
Among the following groups the group that deactivates the benzene ring for further electrophilic substitution is:
  • Methyl
  • Amino
  • Hydroxyl
  • Chloro
On mixing a certain alkane with chlorine and irradiating it with ultraviolet light, it forms only one monochloroalkane. This alkane could be :
  • neopentane
  • propane
  • pentane
  • isopentane
Which of the following statement is correct in relation to the halogenation of alkane?
  • The reactivity of chlorine is less than bromine towards alkanes.
  • For photochemical chlorination of methane, CI is formed in slowest step.
  • Free radicals are pyramidal intermediate, stabilised by hyperconjugation and resonance.
  • Bromine has much higher regioselectivity than chlorine in abstracting $$3^{\circ}$$ hydrogen.
Benzene reacts with n - propyl chloride in the presence of anhydrous $$AlCl_3$$ to give predominantly:
  • n - propylbenzene
  • isopropylbenzene
  • 3 - propyl - 1 - chlorobenzene
  • no reaction
Identify the aromatic compound?
Which of the following alkanes can be synthesized by the Wurtz reaction in good yield?
  • $$(CH_3)_2CH - CH_2 - CH (CH_3)_2$$
  • $$(CH_3)_2CH - CH_2 - CH_2 - CH(CH_3)_2$$
  • $$CH_3 - CH_2 - C(CH_3)_2CH_2 - CH_3$$
  • $$(CH_3)_3C - CH_2 - CH_2 - CH_3$$
The reaction least likely to occur is:
The increasing order of stability of the following free radicals is:
  • $$(CH_2)_2\, \dot{C}H\, <\, (CH_3)_3\, \dot{C}\, <\, (C_6H_5)_2\, \dot{C}H\, <\, (C_6H_5)_3\, \dot{C}$$
  • $$(C_6H_5)_2\, \dot{C}\, <\, (C_6H_5)_2\, \dot{C}H\, <\, (CH_3)_3\, \dot{C}\, <\, (CH_3)_2\, \dot{C}H$$
  • $$(C_6H_5)_2\, \dot{C}H\, <\, (C_6H_5)_3\, \dot{C}H\, <\, (CH_3)_3\, \dot{C}\, <\, (CH_3)_2\, \dot{C}H$$
  • $$(CH_3)_2\, \dot{C}H\, <\, (CH_3)_3\, \dot{C}\, <\, (C_6H_5)_3\, \dot{C}H\, <\, (C_6H_5)_2\, \dot{C}H$$
Which statements is/are correct about photochemical chlorination of the above compound?
$$Ph-CH_2-\overset{CH_3}{\overset{|}{C}H} - CH_3\xrightarrow[(monochlorination)]{Cl_2/h\upsilon }$$
  • The major product will have chiral carbon atom but is optically inactive.
  • The intermediate free radical of the major product is resonance stabilised.
  • The intermediate free radical is tertiary for major product.
  • The intermediate free radical is planar, and stabilised by only hyper conjugation.
The number of total product produced upon monochloriation of (+) 2-chlorobutane is ___________.
  • 3
  • 4
  • 5
  • 6
Which reaction would not give propene?
  • Adding excess hot concentrated sulfuric acid to $$propan-1-ol$$
  • Adding warm aqueous sodium hydroxide to $$2-bromopropane$$
  • Adding warm ethanolic sodium hydroxide to $$1-bromopropane$$
  • Passing $$propan-2-ol$$ vapour over heated aluminium oxide
2-Methyl butane on reacting with bromine in the presence of sunlight gives mainly:
  • 1-Bromo-3-methylbutane
  • 1-Bromo-2-methylbutane
  • 2-Bromo-3-methylbutane
  • 2-Bromo-2-methylbutane
l-bromo-3-chloro cyclobutane will react with two moles of Na in ether producing:
The general molecular formula of alkynes is______________.
  • $$C_nH_{2n}$$
  • $$C_nH_{2n\, -\, 4}$$
  • $$C_nH_{2n\, -\, 2}$$
  • $$C_nH_{2n\, +\, 2}$$
In an alkane if the value of n = 19, it is:
  • solid
  • liquid
  • gaseous
  • none of the above
Among the following compounds 2, 3-dimethylexane is :
314665.png
  • i
  • ii
  • iii
  • iv
Methane with the Molecular formula $$"CH_4"$$ has
  • $$4$$ Covalent bonds
  • $$8$$ Covalent bonds
  • $$6$$ Covalent bonds
  • $$2$$ Covalent bonds
Calcium carbide reacts with water to produce a gas which is used for ripening of fruits like bananas. The gas is a hydrocarbon containing a triple bond in it. The general molecular formula of the homologous series to which the gas belongs is :
  • $$C_nH_{2n+1}OH$$
  • $$C_nH_{2n+2}$$
  • $$C_nH_{2n}$$
  • $$C_nH_{2n-2}$$
Which of the following is properly matched?
  • Kerosene - $$C_5\, -\, C_{10}$$
  • Diesel oil - $$C_5\, -\, C_6$$
  • Petrol - $$C_7\, -\, C_9$$
  • All are correct
The boiling point will increase in the order of:
  • n-butane< iso-butane
  • n-butane <= iso-butane
  • n-butane= iso-butane
  • iso-butane< n-butane
Equal weights $${C}_{2}{H}_{6}$$ and hydrogen are mixed in an empty container at $${0}^{o}C$$. The fraction of total pressure exerted by hydrogen is-
  • $$1:2$$
  • $$1:1$$
  • $$1:16$$
  • $$15:16$$
Which of the following having delocalised electrons?
  • Benzene
  • Cyclohexane
  • $$CH_4$$
  • $$C_2H_6$$
X compound reacts with Na to give $$CH_3CH_2CH_2CH_3$$. The compound X is:
  • $$CH_3 CH_2 OH$$
  • $$CH_3 CH_2 - Cl$$
  • $$CH_3 - CH_3$$
  • $$CH_3 - CH_2 - CH_2 - CH_2 - OH$$
$$H - C \equiv C - H$$ is a structure of :
  • acetaldehyde
  • ethanal
  • ethane
  • acetylene
For which of the following compounds the least number of a mono-chlorinated product is possible?
  • $$CH_3 CH_2 CH_2 CH_2 CH_3$$
  • $$CH_3 - \underset{CH_3}{\underset{|}{C}H} - CH_2 CH_3$$
  • $$CH_3 -\!\!\!\!\! \underset{\,\,\,\,CH_3}{\underset{|}{\overset{\quad CH_3}{\overset{|}{C}}} \!\!\!\!-}\, H$$
  • $$CH_3 -\!\!\!\!\! \underset{\,\,\,\,CH_3}{\underset{|}{\overset{\quad CH_3}{\overset{|}{C}}} \!\!\!\!-} \,CH_3$$
The compound formed when ethyl alcohol is treated with conc.$${H}_{2}{SO}_{4}$$ at $${170}^{o}C$$ is _______.
  • ethane
  • ethene
  • ethyne
  • ethanal
Which of the following compounds on hydrolysis produces methane?
  • $$Ca{CN}_{2}$$
  • $$Ca{C}_{2}$$
  • $${Al}_{4}{C}_{3}$$
  • $$SiC$$
Ethylene is a/an :
  • saturated hydrocarbon
  • alkene
  • paraffin
  • aromatic compound
Which one of the following lists the alkane in order of decreasing boiling point?
  • Octane, Methane, Butane, Ethane
  • Methane, Ethane, Propane, Butane
  • Hexane, Octane, Propane, Methane
  • Hexane, Pentane, Propane, Ethane
Methyl acetylene is also known as :
  • butyne
  • propyne
  • ethyne
  • pentyne
_________ on heating with alcoholic potash loses one molecule of hydrogen halide to give alkene.
  • Halogens
  • Haloalkanes
  • Haloakynes
  • None of the above

What is the reagent used and appropriate temperature required to prepare ethene from ethyl alcohol?
  • Dilute $$H_2SO_4 , 160^\circ C$$
  • Concentrated $$H_2SO_4 , 170^\circ C$$
  • Dilute $$HCl, 170 ^\circ C$$
  • Concentrated $$HCl , 160^\circ C$$
In dehydration of alcohol, a molecule of ________ is eliminated from an alcohol molecule by heating the alcohol.
  • carbon
  • hydrogen
  • water
  • oxygen
Which compounds are aromatic?
444180_ac90b415811046959f7cd97224f3d60b.png
  • (i) & (iii)
  • (ii) & (iv)
  • (i) & (ii)
  • (iii) & (iv)
For production of alkene, alcohol is heated in presence of:
  • conc. $$H_2SO_4$$
  • conc. $$H_3PO_4$$
  • anhydrous $$ZnCl_2$$
  • all of the above
Which of the following represents alkynes?
  • -C-C
  • -C=C-
  • -C $$\equiv $$ C -
  • none of these
Alkenes can be easily obtained by _______ of alkynes.
  • Hydrogenation
  • Oxidation
  • Reduction
  • Halogenation
Alkene can be produced by:
  • dehydration of alcohols
  • dehydrohalogenation of alkyl halides
  • dehalogenation of haloalkanes
  • all of above
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