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

Question. The IUPAC name of CH₃CHOHCH₂CH(CH₃)CHO is
(a) 2-hydroxy-4-methyl-pentanal 
(b) 4-hydroxy-2-methyl-pentanal
(c) 2-hydroxy-2-methyl-pentanal
(d) 2-methyl-pent-4-ol-l-al   
Answer: a

Question. The highest electrical conductivity of the following aqueous solutions is of 
(a) 0.1 M difluoroacetic acid
(b) 0.1 M fluoroacetic acid
(c) 0.1 M chloroacetic acid
(d) 0.1 M acetic acid     
Answer: a

Question. Which compound shows geometrical isomerism among the following? 
(a) CH3—C—H
              ll
     CH₃—C—H
             CH₃
             l
(b) HO—C—H
             l
           COOH
(c) CH₃CH₂ — CH₂CH₃
(b) CH₃CH₂COOC₂CH₅   
Answer: a

Question. Eno! content is highest in 
(a) acetone
(b) acetophenone
(c) acetic acid
(d) acetyl acetone 
Answer: d

Question. Which of the following is a pair offunctionaI isomers?
(a) CH₃COCH₃, CH₃CHO 
(b) C₂H₅CO₂H,CH₃CO₂CH₃
(c) C₂H₅CO₂H, CH₃CO₂C₂H₅
(d) CH₃CO₂H, CH₃CHO   
Answer: b

Question. Inductive effect involves 
(a) delocalisation of σ-electrons
(b) displacement of σ-electrons
(c) delocalisation of n-electrons
(d) displacement of n-electrons   
Answer: c

Question. The IUPAC name of C₆H₅COCl is
(a) benzoyl chloride
(b) benzene chloro ketone
(c) benzene carbonyl chloride
(d) chloro phenyl ketone 
Answer: a

Question. What is the formula of tertiary butyl alcohol? 
(a) CH₃—CH(CH₃ )—CH₂—OH
(b) CH₃—(CH₂ )₂ OH
(c) CH₃—CH(OH)—CH₂—CH₃
(d) (CH₃)₃ ·C—OH     
Answer: d

Question. The IUPAC name of CH₃—CH—CH= C—CHO is
                                            l              l
                                          OH         CH₃
(a) 4-hydroxy-1-methylpentanal 
(b) 4-hydroxy-2-methylpent-2-en-1-al
(c) 2-hydroxy-4-methylpent-3-en-5-al
(d) 2-hydroxy-3-methy lpent-2-en-5-al      
Answer: a

Question. The IUPAC name of the compound CH₃CONHBr is
(a) 1-bromoacetamide 
(b) ethanoylbromide
(c) N-bromoethanamide
(d) None of the above 
Answer: c

Question. The IUPAC name of the compound (CH₃ )₂ CH—CH=CH—CHOH—CH₃ is 
(a) 5-methylhex-3-en-2-ol
(b) 2-methylhex-3-en-5-ol
(c) 2-hydroxy-5-methyl-3-hexene
(d) 5-hydroxy-2-methyl-3-hexene     
Answer: a

Question. The stability of Me₂C= CH₂ is more than that of Me CH₂CH=CH₂ due to the 
(a) inductive effect of Me groups
(b) resonance effect of Me groups
(c) hyperconjugative effect of the Me group
(d) resonance as well as inductive effect of Me group     
Answer: c

Question. Which of the following species does not exert a resonance effect? 
(a) C₆H₅NH₂
(b) C₆H₅N⁺H3
(c) C₆H₅OH
(d) C₆H₅Cl 
Answer: b

Question. The correct order for homolytic bond dissociation energies (ΔH in kcal/mol) for CH₄ (A),C₂H₆ (B) and CH₃Br (C), under identical experimental conditions, is 
(a) C > B > A
(b) B > C > A
(c) C > A > B
(d) A > B > C   
Answer: d

Question. Which of the following is possessed by a nucleophile?
(a) A lone pair of electron 
(b) Positive charge
(c) Negative charge
(d) None of the above 
Answer: a

Question. IUPAC name of CH₃CH₂C(Br) = CH—Cl is
(a) 2-bromo-1-chloro butene-1 
(b) 1-chloro-2-bromo butene-1
(c) 3-chloro-2-bromo butene-2
(d) None of the above         
Answer: a

Question. The IUPAC name of CH₃—C—CH—CH₃ is
                                           ll     l
                                           O   CH₃
(a) 2-methyl-3-butanone
(b) 3-methyl-butan-2-one
(c) 3-methyl butanone
(d) None of the above 
Answer: a

Question. Which of the following resonating structures of 1-methoxy-1, 3-butadiene is least stable?
        ^{_{Θ                            ⊕
(a) CH2 — CH=CH — CH=O—CH3 
(b) CH2=CH2 – CH — CH=O—CH3
      Θ        ⊕
(c) CH2 — CH—CH=CH—O—CH3 
                     Θ     ⊕
(d) CH2=CH—CH—CH—O—CH3}}   
Answer: c

Question. n-pentane and 2-methylbutane is a pair of
(a) enantiomers
(b) stereo isomers
(c) diastereomers
(d) constitutional isomers   
Answer: d

Question. Formic acid is a stronger acid than acetic acid. This can be explained using 
(a) + M-effect
(b) – I-effect
(c) + I-effect
(d) – M-effect   
Answer: a

Question. Geometrical isomerism is reflected by which of the compounds?
(a) 3-phenyl- 1-butene
(b) 2-phenyl- 1 -butene
(c) 1, 1-diphenyl-1-propene
(d) 1-phenyl-2-butene   
Answer: d

Question. The number of possible structural isomers of butene are
(a) 3
(b) 2
(c) 4 
(d) 5
(e) 1     
Answer: a

Question. CH₃CH₂Cl undergoes homolytic fission, produces .
            •           •
(a) CH₃CH₂ and Cl
            ⊕
(b) CH₃CH₂ and Cl
           ⊕           •
(c) CH₃CH₂ and Cl
            •           
(b) CH₃CH₂ and Cl   
Answer: a

Question. Inductive effect involves
(a) displacement of σ electrons
(b) delocalization of π electrons
(c) delocalization of σ-electrons
(d) displacement of π-electrons
Answer: a

Question. 59 g of an amide obtained from a carboxylic acid, RCOOH, liberated 17 g of ammonia upon  heating with alkali. The acid is
(a) Formic Acid
(b) Acetic Acid
(c) Propionic Acid
(d) Benzoic Acid
Answer: b

Question. 0.5 g of hydrocarbon gave 0.9 g water on combustion. The percentage of carbon in hydrocarbon is
(a) 75.8
(b) 80.0
(c) 56.6
(d) 28.6
Answer: b

Question. A gas mixture contains 50% helium and 50% methane by volume. What is the percent by weight of methane in the mixture
(a) 75%
(b) 50%
(c) 80.03%
(d) 19.97%
Answer: c

Question. Which among the following is formed when an alcohol is dehydrated?
(a) alkane
(b) alkyne
(c) alkene
(d) aldehyde
Answer: c

Question. A solution of(+) – 2 – chloro – 2 – phenylethane in toluene racemises slowly in the presence of small amounts of SbCl5 due to the formation of
(a) Carbanion
(b) Carbene
(c) Free radical
(d) Carbocation 
Answer: d

Question. If two compounds have the same empirical formula but different molecular formula they must have
(a) Different percentage composition
(b) Different molecular weight
(c) Same viscosity
(d) Same vapour density
Answer: b

Question. Which of the following physical properties differ for each of a pair of enantiomers?
(a) solubility in ethanol
(b) direction of rotation of plane-polarized light
(c) boiling point and melting point
(d) index of refraction
Answer: b

Question. Which among the following statement is not true?
(a) In liquid, particles are less regularly arranged and are free to move
(b) Boiling involves breaking up of group of molecules in liquid
(c) Boiling involves separation of oppositely charged ions
(d) Thermal energy of particles overcome cohesive forces that hold them
Answer: c

Question. What is the state of hybridisation of carbon in carbanion?
(a) sp
(b) sp²
(c) sp³
(d) sp²d.
Answer: c