CBSE Class 11 Chemistry Organic Chemistry Some Basic Principles and Techniques MCQs Set 03

Question: Methoxyethane and propanol are the examples of isomerism of the type
a) structural
b) position
c) functional
d) tautomerism
Answer: c

Question: Which of the following Fischer's projection fommla is identical to D-glyceraldehyde?

Answer: b

Question: Metamers of ethyl propionate are
a) C₄H₉COOH and HCOOC₄H₉
b) C₄H₉COOH and CH₃COOC₃H₇
c) CH₃COOCH₃ and CH₃COOC₃H₇
d) CH₃COOC₃H₇ and C₃H₇COOCH₃
Answer: d

Question: n-pentane, iso-pentane and neo-pentane are examples for isomers of the type 
a) geometrical
b) optical
c) chain
d) positional
Answer: c

Question: Different structures generated due to rotation about, C—C axis, of an organic molecule, are examples of 
a) geometrical isomerism
b) conformational isomerism
c) optical isomerism
d) structural isomerism
Answer: b 

Question: For which of the following parameters the structural isomers C₂H₅OH and CH₃OCH₃ would be expected to have the same values? (Assume ideal behaviour)
a) Heat of vaporisation 
b) Vapour pressure at the same temperature
c) Boiling points
d) Gaseous densities at the same temperature and pressure
Answer: d

Question: Maximun1 enol content is in

Answer: b

Question: Which organic structure among the following is not an isomer of the compound CH₃–CO–CH₂CH₂CH₂CH₃ ?
a) CH₃CH₂OCH =CHCH₂CH₃
b) CH₃CH = CHCH₂CH₂CHO
c) (CH₃)₂CH–CO–CH₂CH₃
d) CH₃CH₂COCH₂CH₂CH₃
Answer: b

Question: Select the molecule which has only one π-bond
a) CH ≡ CH
b) CH₂ = CHCHO
c) CH₃CH = CH₂
d) CH₃CH=CHCOOH
Answer: c

Question: Increasing order of stability among the three main conformations, (i.e. Eclipse, Anti, Gauche) of 2-fluoroethanol is 
a) Eclipse, Gauche, Anti
b) Gauche, Eclipse, Anti
c) Eclipse, Anti, Gauche
d) Anti, Gauche, Eclipse
Answer: c

Question: The compounds CH₃CH == CHCH₃ and CH₃CH₂CH == CH₂ 
a) are tautomers
b) are position isomers
c) contain same number of sp³– sp³, sp³– sp² and sp²– sp² carbon-carbon bonds
d) exist together in dynamic equilibrium
Answer: b

Question: Heterolytic fission of C – Br bond results in the formation of
a) free radical
b) carbanion
c) carbocation
d) Both carbanion and carbocation
Answer: c

Question: Geometrical isomerism is possible in case of
a) pentene-2
b) propane
c) pentane
d) ethene
Answer: a 

Question: In this reaction,
CH₃CHO+HCN → CH₃CH(OH)CN
→^H·OH CH₃CH(OH)COOH
an asymmetric centre is generated. The acid obtained would be 
a) 50% D + 50% L-isomer
b) 20% D + 80% L-isomer
c) D-isomer
d) L-isomer 
Answer: a

Question: The number of isomers of the compound with molecular fommla C₂H₂Br₂ is 
a) 4
b) 3
c) 5
d) 2
Answer: d

Question: C₆H₅C = N and C₆H₅N = C exhibit which type of isomerism? 
a) Position
b) Functional
c) Metamerism
d) Dextro-isomerism
Answer: b 

Question: How many isomers are possible for the alkane C₄H₁₀ ?
a) 3
b) 5
c) 2
d) 4
Answer: c

Question: The number of primary, secondary, tertiary and quaternary carbons in neopentane are respectively
a) 4, 3, 2 and 1
b) 5, 0, 0 and 1
c) 4, 0, 0 and 1
d) 4, 0, 1 and 1
Answer: c

Question: Which of the following compounds contains 1°, 2°, 3° as well as 4° carbon atoms ?
a) Neopentane
b) 2-methyl pentane
c) 2,3-dimethyl butane
d) 2,2,3-trimethyl pentane
Answer: d

Question: The number of secondary hydrogens in 2, 2-dimethylbutane is
a) 8
b) 6
c) 4
d) 2
Answer: d

Question: The organic reaction which proceed through heterolytic bond cleavage are called ________
a) ionic
b) polar
c) nonpolar
d) Both ionic and polar
Answer: d

Question: Which of the following statements is false for isopentane ?
a) It has three CH₃ groups
b) It has one CH₂ group
c) It has one CH group
d) It has a carbon which is not bonded to hydrogen
Answer: d

Question: The IUPAC name of neopentane is
a) 2, 2-dimethylpropane
b) 2-methylpropane
c) 2, 2-dimethylbutane
d) 2-methylbutane
Answer: a

Question: The IUPAC name of the compound CH₃ — CH(CH₃) — CO – CH₃, is
a) 3-methyl 2-butanone
b) 2-methyl 3-butanone
c) isopropyl methyl ketone
d) methyl isopropyl ketone
Answer: a

Question: Total number of structural isomers possible for C₃H₆ are :
a) 2
b) 1
c) 4
d) 3
Answer: a

Question: Which of the following molecules is expected to rotate the plane of plane polarised light?

First organic compound to be synthesised was
a) methane
b) cane sugar
c) acetic acid
d) urea
Answer: a

Question: Which of the following statements is false for isopentane–
a) It has three CH₃ groups
b) It has one CH₂ group
c) It has one CH group
d) It has a carbon which is not bonded to hydrogen
Answer: d

Question: The IUPAC name of the compound CH₃OCH₂CH₂CH₂OCH₂CH₃ is
a) 3-ethoxy-1-methoxypropane
b) 1-ethoxy-3-methoxypropane
c) 2, 5-dioxyhexane
d) ethoxypropane oxymethane
Answer: a

Question: Which of the following compounds is optically active ?
a) (CH₃ )₂CHCH₂OH
b) CH₃CH₂OH 
c) CCI₂F₂
d) CH₃CHOHC₂H₅
Answer: d 

Question: C6H5C ≡ N and C6H5N ≡ C are which type of isomers?
a) Position
b) Functional
c) Tautomerism
d) Linkage
Answer: b

Question: A functional isomer of 1-butyne is
a) 2-butyne
b) 1-butene
c) 2-butene
d) 1, 3-butadiene
Answer: d

Question: In which of the following, functional group isomerism is not possible?
a) Alcohols
b) Aldehydes
c) Alkyl halides
d) Cyanides
Answer: c

Question: Which one of the following shows functional isomerism?
a) C₂H₄
b) C₃H₆ 
c) C₂H₅OH
d) CH₂Cl₂
Answer: c

Question: The least number of carbon atoms in alkane showing isomerism is
a) 3
b) 1
c) 2
d) 4
Answer: d

Question: The number of possible alkynes with molecular formula C₅H₈ is
a) 2
b) 3
c) 4
d) 5
Answer: b

Question: The functional group present in organic, acid is –
a) – OH
b) – CHO
c) –COOH
d) > C = O
Answer: c

Question: Amongst the following compounds, the optically active alkane having lowest molecular mass is

Answer: c

Question: How many asymmetric carbon atoms are present in
I. 1,2-dimethylcyclohexane
II. 3-methylcyclopentane and
III. 3-methylcyclohexene ?
a) Two, one, one
b) One, one, one
c) Two, none, two
d) Two, none, one
Answer: d