CBSE Questions for Class 11 Medical Chemistry Hydrocarbons Quiz 12 - MCQExams.com

The balance chemical equations for the following :
Reaction between 1, 2 - dibromoethane & alcoholic potassium hydroxide.
  • $$CH_2Br-CH_2Br \xrightarrow {alc. KOH} CH_3-CH_2Br \xrightarrow {NaNH_2} CH \equiv CH$$
  • $$CH_2Br-CH_2Br \xrightarrow {alc. KOH} CH_2Br-CHBr \xrightarrow {NaNH_2} CH \equiv CH$$
  • $$CH_2Br-CH_2Br \xrightarrow {alc. KOH} CH_2=CHBr \xrightarrow {NaNH_2} CH \equiv CH$$
  • $$CH_3-CH_2Br \xrightarrow {NaNH_2} CH_2 = CH_2$$
$$Et{NH}_{2}+MeMgI\xrightarrow [ in\quad the\quad presence\quad of\quad pyridine ]{ Heated\quad in\quad high\quad temp. }  Gas (A)$$
The volume of gas $$(A)$$ obtained at S.T.P when $$0.45gm$$ of $$Et{NH}_{2}$$ reacts with $$MeMgI$$ is:
  • $$224ml$$
  • $$22.4ml$$
  • $$448ml$$
  • $$44.8ml$$
What are the numerical values of N and M?
243883.jpg
  • 6,6
  • 5,4
  • 4,4
  • 3,3
Which of the following statements is/are correct?
  • Molecular formula or molecular mass of a gaseous hydrocarbon can be determined even without knowing their percentage composition by audiometry
  • In Lassaigne's test, N and S both present in the organic compounds are converted into $$\overset{\circleddash}{C}NS$$ ion
  • $$K_2SO_4$$ and $$CuSO_4$$ are added in Kjeldahl's method. $$K_2SO_4$$ acts as a catalyst while $$CuSO_4$$ raises the boiling point of $$H_2SO_4$$
  • Layer test is used to distinguish $$Cl^{\circleddash}$$ and $$Br^{\circleddash}$$ ions
trans-3, 6-Dimethyl oct-4-ene (A) exists in two diastereomers (I) and (II). Which statement is true about (I) and (II).
If the stereochemistry about the double bond in (A) is trans, two diastereomers (I) and (II) exist as shown in. Which statement is correct ?
  • (I) is optically inactive due to the presence of plane of symmetry.
  • (I) is optically inactive due to the presence of centre of symmetry.
  • (II) is optically inactive due to the presence of plane of symmetry.
  • (II) is optically inactive due to the presence of centre of symmetry.
$$CH_3-(CH_3)CH-CH_2-CH_3 \xrightarrow {Cl_2,\ hv} N (\text{isomeric products})$$
$$\ C_5H_{11}Cl \xrightarrow {\text{fractional distillation}} M(\text{isomeric products})$$
What are N and M (N and M are number of products formed) ?
  • 6, 6
  • 6, 4
  • 4, 4
  • 3, 3
Assertion : Chlorination of allylic hydrogen is difficult than vinylic hydrogen.
Reason : Allyl radical is stabilised by resonance.
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Assertion is incorrect but Reason is correct
  • Both Assertion and Reason are incorrect
Give the structure of reactants :
248285_21f61ac02d99441ebb9a1b42f59500b3.png
  • A: Benzaldehyde  B: Acetylene
  • A: Benzyl alcohol B: Ethanol
  • A: Benzoic acid  B: Acetylene
  • A: Phenol  B: Acetylene

Which of the following statement(s) is correct?
249226_e53cea56b0174a408c678d65c26fff47.png
  • The compound (B) is
  • The compound (B) is
  • The compound (A) on reaction with HI + Red P gives
  • The compound (A) on oxidation with $$MnO_2$$ gives
What is the major product formed when methylenecyclohexane reacts with NBS?
  • 1 bromo 1 bromomethyl cylohexane
  • 1 bromo 2 methylene cyclohexane
  • 1-(bromomethyl)cyclohexene
  • none of these
Correct order of boiling point is:
Consider the reaction

$$\left[CH_3CH_2CH_2-\!\!\!\!\!\underset{\,\,\,\,CH_3}{\underset{|}{\overset{\quad CH_3}{\overset{\!\!\!+|}{N}}}\!\!\!\!-}CH_2CH_3\right]OH^- \xrightarrow{Heat}$$

Which of the following is formed in major amount?
  • CH$$_2$$=CH$$_2$$
  • CH$$_3$$CH=CH$$_2$$
  • Both (A) and (B) in equal amount
  • None, as no reaction takes place
$$\left[CH_3CH_2CH_2-\!\!\!\!\!\!\underset{\,\,\,\,\,CH_3}{\underset{|}{\overset{\,\,\,\,\,\,\,CH_3}{\overset{\!\!\!\!\!+|}{N}}}\!\!\!\!\!-}CH_2CH_3\right]OH^- \xrightarrow{Heat}$$
Consider the reaction Which of the following is formed in major amount?
  • $$CH_2=CH_2$$
  • $$CH_3CH_2=CH_2$$
  • Both (1) and (2) in equal amount
  • None, as no reaction takes place
Arrange the following in increasing/decreasing order of boiling point :
$$\underset{I}{CH_3CH_2CH_2CH_2CH_3}, \   \, \underset{II}{(CH_3)_2 CHCH_2CH_3},\  \  \underset{III}{(CH_3)_4C}$$
  • I > II > III
  • II > I > III
  • III > I > II
  • III < II < I
With the help of the following equations and data choose the wrong statement.
249809_972d10228a1c47609f36b1aa3e16e26e.png
  • Thermal cracking of (CH) bond of methane occurs at 1500 K and that of (CH) bond of ethane breaks at 800900 K.
  • During homolysis of ethane at high temperature, the (CC) bond breaks more radily than (CH) bonds.
  • During the cracking of n-butane, reaction (IV) occurs more readily than reaction (V).
  • Formation of $$CH_3CH_2$$ radical by reaction (II) will take place at lower temperature than the formation of $$C_2H_5$$ radical by reaction (IV).
Which of the following reactions will not give four-membered cyclic compound?
  • $$2CH_2\, =\, CH_2\, \xrightarrow{hv}\, C$$
Chloroform reacts with oxygen in the presence of light to give:
  • carbon tetrachloride
  • carbonyl chloride
  • methyl chloride
  • methylene dichloride
  • acetaldehyde
Which of the following elimination reactions will occur to give but-1-ene as the major product?
$$C_2H_6+Cl_2 \xrightarrow{sunlight}Q$$
                                    $$\downarrow aq. KOH$$
                              $$C_2H_5OH \xrightarrow[K_2Cr_2O_7]{[O]} R \xrightarrow{C_2H_5OH} S$$
Identify Q and S.
  • Q = Chloroethene, S = Ester
  • Q = Chloroethene, S = Ethanoic acid
  • Q = Chloroethane, S = Ester
  • Q = Chloroethane, S = Ethanoic acid
$$X$$ is an optically active alkane having lowest molecular mass, predict the structure of the major product obtained on monochlorination of $$X$$.
  • $$CH_3-CH_2-CH_2-\underset{Cl}{\underset{|}{\overset{CH_3}{\overset{|}C}}}-CH_2-CH_3$$
  • $$CH_3-CH_2-CH_2-\overset{CH_3}{\overset{|}{C}H}-\underset{\!\!\!Cl}{\underset{|}{C}H}-CH_3$$
  • $$CH_3-CH_2-CH_2-\overset{CH_3}{\overset{|}{C}H}-CH_2-CH_2-Cl$$
  • $$Cl-CH_2-CH_2-CH_2-\overset{CH_3}{\overset{|}{C}H}-CH_2-CH_3$$
Arrange the reactions given below in proper sequence for the conversion of ethane to methane.
(a) Treatment with sodium hydroxide
(b) Treatment with aqueous $$KOH$$
(c) Treatement with $$NaOH+CaO$$
(d) Halogenation
(e) Reaction with acidified $${K}_{2}{Cr}_{2}{O}_{7}$$
  • $$e\ a\ d\ b\ c$$
  • $$d\ b\ e\ a\ c$$
  • $$e\ c\ b\ a\ d$$
  • $$d\ e\ a\ b\ c$$
The common name of 2-Butyne is :
  • acetylene
  • methyl acetylene
  • ethyl acetylene
  • dimethyl acetylene
Which of the following aromatic compound gives sulphonation reaction very easily?
  • Chlorobenzene
  • Nitrobenzene
  • Toluene
  • Benzene
Two metals $$X$$ and $$Y$$ have $$3$$ and $$2$$ electrons in their valence shells $$'M'$$ and $$'N'$$ respectively. These metals can form binary compounds $$A$$ and $$B$$ with the same non-metal carbon. Both $$A$$ and $$B$$ can undergo hydrolysis forming hydrocarbons $$C$$ and $$D$$. Identify $$C$$ and $$D$$.
  • $${C}_{6}{H}_{6}, {C}_{3}{H}_{4}$$
  • $${C}_{3}{H}_{6}, {C}_{3}{H}_{4}$$
  • $${CH}_{4}, {C}_{2}{H}_{2}$$
  • $${C}_{4}{H}_{10}, {C}_{3}{H}_{6}$$
Which of the following solvents should be added to the organic solvent containing the pentane in order to remove the impurities in a separate layer that will not mix with the organic solvent?
  • $$CCl_{4}$$
  • $$C_{6}H_{6}$$
  • $$HF$$
  • $$SH_{2}$$
A hydrocarbon on ozonolysis gives one mole each of compounds $$A$$ and $$B$$. Both $$A$$ and $$B$$ on reduction with sodium borohydride gives compounds $$C$$ and $$D$$ belonging to same homologous series. $$C$$ has no position isomer whereas $$D$$ has position isomer. $$A$$ and $$B$$ do not belong to the same homologous series. However, both $$A$$ and $$B$$ on oxidation with acidified $$KMn{O}_{4}$$ give same compound. Identify the hydrocarbon.
  • 3- Methyl-2-butene
  • 2,3-Dimethyl-1-butene
  • 2-Methyl-2-butene
  • 3,4-Dimethyl-1-butene
Which of the following is NOT correct?
  • $$LiOH$$ is a weaker base than $$NaOH$$.
  • Salts of $$Be$$ undergo hydrolysis.
  • $$Ca{ \left( HC{ O }_{ 3 } \right) }_{ 2 }$$ is soluble in water.
  • Hydrolysis of beryllium carbide gives acetylene.
The product formed when toulene is heated in light with $${Cl}_{2}$$ and in absence of halogen carrier is:
  • Chlorobenzene
  • Gammexene
  • Benzotrichloride
  • DDT
Which of the following statements is false regarding the reaction between $$Cl_2$$ and $$C_2H_6$$?
  • It is a substitution reaction
  • The reaction will give a single product of $$C_2H_5Cl$$
  • The reaction mechanism involves free radicals
  • The reaction can be initiated with either sunlight or heat
Which of the following compounds is the slowest to react the nitrosonium ion$$(NO^+)$$?
Acetylene can be obtained by the reaction:
  • $$HCOOK \xrightarrow{Electrolysis}$$
  • $$CHI_3 + Ag \xrightarrow{\Delta}$$
  • $$CH_3 CH_2 OH \xrightarrow[443 K]{Conc. H_2SO_4}$$
  • $$Be_2C+ H_2O \rightarrow$$
The arrangement of following compounds:
$$i$$. Bromomethane
$$ii$$. Bromoform
$$iii$$. Chloromethane
$$iv$$. Dibromomethane
In the increasing order of their boiling point is :
  • $$iii< i< iv< ii$$
  • $$iv< iii< i< ii$$
  • $$ii< iii< i< iv$$
  • $$i< ii< iii< iv$$
Which one of the following is not formed when a mixture of methyl bromide and bromobenzene is heated with sodium metal in the presence of dry ether?
  • Ethane
  • Diphenyl
  • Propane
  • Toluene

Which of the following does not give isopropylbenzene as a product upon reaction with benzene?
  • $$(CH_3)_2CHCl/AlCl_3$$
  • $$CH_3CH_2CH_2Cl/AlCl_3$$
  • $$CH_3CH=CH_2/H_3PO_4$$
  • $$(CH_3)_2C=CH_2/H_3PO_4$$
Large molecule alkane on heating at a high temperature forms low molecular alkane and alkene by a process called as___________.
  • Cracking
  • Dehydrogenation
  • Hydration
  • Both a and b
The end product $$C$$ in the given reaction is:

659557_4c04bac03e334f4a9d7a64c49677b25f.png
Freon 12 is manufactured from $$C{ Cl }_{ 4 }$$ by:
  • Wurtz reaction
  • Swarts reaction
  • Fittig reaction
  • Wurtz-Fittig reaction
  • Sandmeyer reaction

The alkene formed as a major product in the above elimination reactions is:
779960_6622b8eba38546aa8b4c3ad182cfb15f.PNG
  • $$CH_2=CH_2$$
The major product formed in the oxidation of acetylene by alkaline $$KMnO_{4}$$ is ________.
  • Ethanol
  • Acetic acid
  • Formic acid
  • Oxalic acid
Which of the following reactions does not occur in practice?
  • $$Ph_{3}CH + CH_{3}(CH_{2})_{3}Na\rightarrow Ph_{3}CNa + CH_{3} (CH_{2})_{2} CH_{3}$$
  • $$CH_3\overset{O}{\overset{||}{C}}CH_2\overset{O}{\overset{||}{C}}CH_3+EtONa \longrightarrow CH_3\overset{O}{\overset{||}{C}}CH =\overset{ONa}{\overset{|}{C}C}H_3+EtOH$$
Only two isomeric monochloro derivatives are possible for:
  • n-Butane
  • 2,4-Dimethylpentane
  • Benzene
  • 2-Methyl propane
Which of the following compounds can be best prepared by Wurtz - reaction?
  • Iso-butane
  • n-butane
  • n-pentane
  • Iso-pentane
Which of the following compounds can be best prepared by Wurtz-reaction?
  • Iso-butane
  • n-butane
  • n-pentane
  • Iso-pentane
When $$n-$$hexane is heated with anhydrous $$AlCl_{3}$$ and $$HCl$$ gas, the major products obtained is:
  • $$1$$-chlorohexane
  • $$2$$-chlorohexane
  • $$3$$-chlorohexane
  • hex-$$3$$-ene
  • mixture of $$2$$-methylpentane and $$3$$-methylpentane
What will be the major product, when 2-methyl butane undergoes bromination:
  • 1-bromo-2-methyl butane
  • 2-bromo-2-methyl butane
  • 2-bromo-3-methyl butane
  • 1-bromo-3-methyl butane
Which one of the following undergoes nucleophilic aromatic substitution at the fastest rate?
The energy required to vapourise one mole of benzene at it's boiling point is $$31.2\ kJ$$. For how long a $$100\ w$$ electric heater has to be operated in order to vaporize a $$100\ g$$ sample of benzene at it's boiling temperature?
  • $$\approx 743\ sec$$
  • $$400\ sec$$
  • $$3.12\times 10^{4} sec$$
  • $$\approx 371\ sec$$
Of the isomeric hexanes, the isomers that give the minimum and maximum number of monochloro derivatives are respectively :
  • 2,3-dimethylbutane and n-hexane
  • 3-methylpentane and 2,3-dimethylbutane
  • 2,3-dimethylbutane and 2-methylpentane
  • 2-methylpentane and 2,2-dimethylbutane
Towards catalytic hydrogenation, the least reactive compound is:
  • $${ CH }_{ 2 }{ \ =\ CH }_{ 2 }$$
  • $${ CH }_{ 3 }\ -\ { CH }{ \ =\ CH }_{ 2 }$$
  • $${ H }_{ 3 }C\ -\ { CH }{ \ =\ CH\ -\ CH }_{ 3 }$$
  • $$({ CH }_{ 3 }{ ) }_{ 2 }C\ =\ C({ CH }_{ 3 }{ ) }_{ 2 }$$
Major product is:
872744_2f77ed3b278041a295d3ab7c781220d4.png
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