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

Question. Electromeric effect is
(a) permanent effect
(b) temporary effect
(c) resonance effect
(d) inductive effect   
Answer: b

Question. The reaction intermediate produced by homolytic cleavage of a bond is called 
(a) carbene
(b) carbocation
(c) carbanion
(d) free radical       
Answer: d

Question. Which kind of fission is favoured by sunlight?
(a) Heterolytic fission
(b) Homolytic fission
(c) Both (a) and (b)
(d) None of these     
Answer: b

Question. What kind of isomerism is possible for 1-chloro-2-nitroethene?
(a) Functional group isomerism
(b) Position isomerism
(c) EIZ isomerism
(d) Optical isomerism   
Answer: c

Question. Which of the following will be chiral ? 
(a) CH₃CHCl₂
(b) CH₃CHBrCl
(c) CD₂Cl₂
(d) CH₂ClBr   
Answer: b

Question. The basicity of aniline is less than that of cyclohexylamine. This is due to 
(a) +R effect of — NH₂ group
(b) – I effect of — NH₂ group
(c) -R effect of — NH₂ group
(d) hyperconjugation effect       
Answer: a

Question. A solution of (- d) 1-chloro-1-phenylelnane in toluene a racemises slowly in the presence of a small amounts of SbCI₅ due to the formation of
(a) carbanion
(b) carbene
(c) carbocation
(d) free radical     
Answer: c

Question. Write the IUPAC name of 
        CH₃—O—CH—CH₂—CH₃
                      l
                     CH₃
(a) 3-methoxybutane
(b) 2-methoxybutane 
(c) 3-methyl-3-methoxypropane
(d) butoxy methane   
Answer: a

Question. IUPAC name of CH₃CH= C—CH₃ is
                                        I
                                       CH₂
                                        I 
                                       CH₃  
(a) 2-ethyl butene
(b) 2-ethyl but-2-ene
(c) 3-methyl pent-2-ene 
(d) None of these   
Answer: c

Question. Amongst the following, the compound that can most readily get sulphonated is 
(a) benzene
(b) toluene
(c) nitrobenzene
(d) chlorobenzene     
Answer: b

Question. +I-effect is shown by 
(a) — CH₃
(b) — Br
(c) — Cl
(d) — NO₂     
Answer: a

Question. Chlorobenzene is o, p -directing in electrophilic substitution reaction. The directing influence is explained by 
(a) + M of Ph
(b) + I of Cl
(c) + M of Cl
(d) – I of Ph 
Answer: c

Question. Among the following compounds, the most acidic is
(a) p-nitrophenol
(b) p-hydroxybenzoic acid
(c) o-hydroxybenzoic acid
(d) p-toluic acid     
Answer: c

Question. Racemic mixture is fonned by mixing two
(a) isomeric compounds
(b) chiral compounds
(c) meso compounds
(d) enantiomers with chiral carbon     
Answer: b

Question. Which of the following shows geometrical isomerism ?
(a) C₂H₅Br
(b) (CH₂) (COOH)₂
(c) (CH)₂ (COOH)₂
(d) C₂H₆       
Answer: c

Question. The compound which contains all the four 1°, 2° ,3° and4° carbon atoms is 
(a) 2, 3-dimethylpentane
(b) 3-chloro-2, 3- dimethylpentane
(c) 2, 3, 4-trimethylpentane
(d) 3, 3-dimethylpentane     
Answer: b

Question. The IUP AC name of acryldehyde is 
(a) prop-2-en-1-al
(b) propenyl aldehyde
(c) but-2-en-1-al
(d) propenal 
Answer: a 

Question. Dichloroacetic acid is a stronger acid than acetic acid. This is due to the occurrence of 
(a) mesometic effect
(b) hyperconjugation
(c) inductive effect
(d) steric effect     
Answer: c

Question. Which of the following has most acidic hydrogen?
(a) 3-hexanone 
(b) 2, 4-hexanedione
(c) 2, 4-hexanedione
(d) 2, 3-hexanedione 
Answer: b

Question. Orbital interaction between the σ-bonds of a substituent group and a neighbouring n-orbital is known as 
(a) hyperconjugation
(b) inductive effect
(c) steric effect
(d) electric quadrapole interaction   
Answer: a

Question. The well known compounds (+)-lactic acid and (—) -lactic acid, have the same molecular formula, C₃H₆O₃. The correct relationship between them is 
(a) constitution isomerism
(b) geometrical isomerism
(c) identicalness
(d) optical isomerism   
Answer: d 

Question. Which of the following is not true for carbanions?
(a) The carbon carrying the charge has eight valence electrons 
(b) They are formed by heterolytic fission
(c) They are paramagnetic
(d) The carbon carrying the charge is sp³-hybridised     
Answer: c

Question. Which one of the following carbanions is the least stable?
(a) CH₃CH^–₂
(b) HC = C^– 
(c) (C₆H₅ )₃ c^–
(d) CH-₃
(e) (CH₃ )₃ C^–       
Answer: e

Question. Nitroethane can exhibit which one of the following kinds of isomerism 
(a) Metamerism
(b) Optical activity
(c) Tautomerism
(d) Position isomerism   
Answer: c

Question. Number ofisomers possible for C₄H₈O is 
(a) 3
(b) 4
(c) 5
(d) 6   
Answer: d

Question. The epoxide ring consists of which of the following?
(a) Three membered ring with two carbon and one oxygen
(b) Four membered ring with three carbon and one oxygen
(c) Five membered ring with four carbon and one oxygen
(d) Six membered ring with five carbon and one oxygen     
Answer: a

Question. IUPAC name of the following compounds is 
                O                    O       
                 ll                    ll
H₃C—CH₂—C—H₂C—CH₂—C—OCH₃
(a) ethyl-4-oxoheptanoate
(b) methyl-4-oxoheptanoate
(c) ethyl-4-oxohexanoate
(d) methyl 4-oxohexanoate     
Answer: d

Question. The compound which gives the most stable carboniwn ionon dehydration is
(a) CH₃CH(CH₃ )CH₂OH
(b) (CH₃ )₃ COH
(c) CH₂ = CHCH₂CH₂OH
(d) CH₃CHOHCH₂ — CH₃   
Answer: b

Question. Which one of the following is not true regarding electromeric effect? 
(a) It is temporary effect
(b) It operates on multiple bonds
(c) It requires on attacking reagent
(d) It results in the appearance of partial charges on the carbon atom     
Answer: d

Question. The correct order of increasing basicity of the given conjugate bases (R = CH₃ ) is 
(a) RCOO < HC=C < R < NH₂
(b) R < HC= C < RCOO< NH₂
(c) RCO < NH₂ < HC=C < R
(d) RCOO< HC=C< NH₂ < R       
Answer: a

Question. Which is the most stable carbocation?
(a) iso-propy1 cation
(b) Triphenylmethyl cation
(c) Ethyl cation
(d) n-propyl cation 
Answer: b

Question. Consider the following carbocations,
I. H₆CH₅C⁺H₂
II. C₆H₅CH₂C⁺H₂
III. C₆H₅C⁺HCH₃
IV. C₆H₅C⁺(H₃)₂
The cotTect sequence of the stability of these is
(a) II < I < III < IV 
(b) II < III < I < IV
(c) III < l < II < IV
(d) IV < III < I < II 
Answer: a

Question. Which one of the nitrogen atoms in
          O
          II
H₂N—NH—C—NH₂ is the most nucleophilic?
    I    II          III
(a) Only III
(b) Only I 
(c) Only II
(d) All three N-atoms       
Answer: b

Question. Disymmetric object is one which is 
(a) superirnposable on its mirror image
(b) non-superimposable on its mirror image
(c) optically inactive
(d) achiral       
Answer: a

Question. PhCHCIBr →^{t BuO-} carbene.
In the reaction, which of the following is most probable?
(a) : CHBr
(b) : CHCl 
(c) : CPhBr
(d) : CPhCl   
Answer: b

Question. Among the following carbocations
      +                              +
Ph₂CCH₂Me (I), PhCH₂CH₂CHPh (II), 
     +                                      +
Ph₂CCH₂Me (III) and Ph₂C(Me )CH₂  (IV), the order of stability is 
(a) IV > II > I > III
(b) I > II > III > IV
(c) II > I > IV > III
(d) I > IV > III > II     
Answer: b

Question. How many chiral compounds are possible on monochlorination of 2-methyl butane?
(a) 8
(b) 2
(c) 4
(d) 6   
Answer: c

Question. Total number C₄H₁₀O is of isomers for the molecular formula
(a) 3
(b) 4
(c) 6
(d)7     
Answer: d

Question. The compound without a chiral carbon atom is 
                CH₃                  
                 l                      
(a) Br CH₂ CHCH₂Br
                    CH₃
                      l       
(b) C₂H₅CH₂ CHCH₂ Br
(c) CH³CH₂ CHCH₂Br
                  l
                 CH₃ 
(d) HOOC CH (Br) COOH
                l 
               CH₃   
(e) OHC—CH(OH)—CH₂OH   
Answer: a

Question. Due to the presence of an unpaired electron, free radicals are 
(a) cations
(b) anions
(c) chemically inactive
(d) chemically reactive 
Answer: d