Q1 · 2019 · 2 marks
The major product in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
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Answer: (b)
CSIR NET Chemical Science — Reagents, Named and Pericyclic Reactions previous year questions
77 questions · 2011–2019 · all with verified answer · last checked 2026-11-10
Q2 · 2019 · 2 marks
The major product in A and B in the following reaction sequence is: 
- (a)
- (b)
- (c)
- (d)
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Answer: (d)
Q3 · Dec 2019 · 2 marks
E1cb mechanism is followed in the reaction of:
- (a) 2-bromopentane with t-BuOK to give pent-2-ene.
- (b) Nitromethane with benzaldehyde in the presence of KOH to give \beta-styrene.
- (c) Bromobenzene with NaNH 2 to give aniline.
- (d) P-chloronitrobenzene with NaOMe to give p -nitroanisole.
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Answer: (b)
Q4 · Dec 2019 · 2 marks
The major product in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
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Answer: (d)
Q5 · Dec 2019 · 2 marks
The major product formed in the following reaction is 
- (a)
- (b)
- (c)
- (d)
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Answer: (a)
Q6 · Dec 2019 · 2 marks
The major product A and the byproducts B formed in the following reaction are 
- (a)
- (b)
- (c)
- (d)
\mathrm{B}=\mathrm{O}=\mathrm{C}=\mathrm{S}, \mathrm{S}=\mathrm{P}(\mathrm{OMe})_{3}
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Answer: (a)
Q7 · Dec 2019 · 2 marks
In the following transformation, the enantiomerically pure lactone A is 
- (a) Equimolar amounts of syn and anti diastereomers of B , both of which are racemic.
- (b) Equimolar amounts of syn and anti diastereomers of B , both of which are enantiomerically pure.
- (c) Only syn diasteroeomer of B, which is racemic.
- (d) Only anti diasteromer of B , which is enantiomerically pure.
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Answer: (c)
Q8 · Dec 2019 · 2 marks
The major product in the following reaction is 
- (a)
- (b)
- (c)
- (d)
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Answer: (b)
Q9 · Dec 2019 · 2 marks
The correct sequence of reactions involved in the following transformation is: 
- (a) Aldol condensation, Michael addition, aldol reaction
- (b) Aldol condensation, aldol reaction, Michael addition
- (c) Michael addition, Aldol condensation, aldol reaction
- (d) Aldol condensation, Michael addition, Michael addition
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Answer: (a)
Q10 · June 2018 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
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Answer: (c)
Q11 · June 2018 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
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Answer: (c)
Q12 · June 2018 · 2 marks
The major heterocyclic compound formed in the following reaction is 
- (a)
- (b)
- (c)
- (d)
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Answer: (c)
Q13 · Dec 2018 · 2 marks
Correct sequence of reagents to be used for the following conversion is- 
- (a) I) NaH, 1-fluoronaphthalene; II) NaBH4; III) i(CH2O)n, Me2NH.HCl; ii. 5 N NaOH
- (b) I) NaBH4; II) NaH, 1-fluoronaphthalene; III) i(CH2O)n, Me2NH.HCl; ii. 5N NaOH
- (c) I) (CH2O)n, Me2NH.HCl; ii. 5N NaOH; II) NaBH4; III) NaH, 1-fluoronaphthalene
- (d) I) i(CH2O)n, Me2NH.HCl; ii. 5N NaOH; II) NaH, 1-fluoronaphthalene
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Answer: (c)
Q14 · Dec 2018 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
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Answer: (a)
Q15 · Dec 2018 · 2 marks
The correct sequence of reagents to be used for the following conversion is- 
- (a) I) \mathrm{LDA}, \mathrm{EtBr}; II) EtLi ; III) \mathrm{H}_{3} \mathrm{O}^{+}
- (b) I) EtLi ; II) \mathrm{LDA}, \mathrm{EtBr}; III) \mathrm{H}_{3} \mathrm{O}^{+}
- (c) I) \mathrm{H}_{3} \mathrm{O}^{+}; II) EtLi ; III) LDA, EtBr
- (d) I) EtLi ; II) \mathrm{H}_{3} \mathrm{O}^{+}; III) \mathrm{LDA}, \mathrm{EtBr}
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Answer: (a)
Q16 · Dec 2018 · 2 marks
Both 1-chloro-1-phenylpropan-2-one and 1-chloro-3-phenylpropan-2-one give same product A when heated in presence of NaOMe. The product A is
- (a) Methyl 3-phenylpropanoate
- (b) Methyl 2- phenylpropanoate
- (c) Methyl 2-methoxy-2-phenylacetate
- (d) 1-methoxy-3-phenylpropan-2-one
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Answer: (a)
Q17 · June 2017 · 2 marks
The major product formed in the sodium ethoxide mediated reaction between benzophenone and chloroacetate is
- (a)
- (b)
- (c)
- (d)
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Answer: (c)
Q18 · June 2017 · 2 marks
The correct combination of reagents to effect the following reaction is: 
- (a) i) \mathrm{POCl}_{3}, pyridine; ii) AgoAc ; iii) \mathrm{LiAlH}_{4}
- (b) i) \mathrm{NaBH}_{4}; ii) \mathrm{Ph}_{3} \mathrm{P}, DEAD, \mathrm{PhCO}_{2} \mathrm{H}
- (c) i) \mathrm{Ph}_{3} \mathrm{P}, \mathrm{DEAD}, \mathrm{PhCO}_{2} \mathrm{H}; ii) \mathrm{LiAlH}_{4}
- (d) i) PCC; ii) L-selectride
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Answer: (c)
Q19 · Dec 2017 · 2 marks
Correct sequence of steps involved in the following transformation is 
- (a) Michael addition, aldol condensation, syn elimination, keto-enol tautomerism
- (b) aldol condensation, electrocyclic ring closing, syn elimination, dehydrogenation
- (c) Michael addition, Claisen condensation, anti-elimination, keto-enol tautomerism
- (d) Robinson annulation, dehydrogenation, anti-elimination
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Answer: (a)
Q20 · June 2017 · 2 marks
Following reaction is an example of 
- (a) Ramberg-Backlund reaction
- (b) [2, 3]-sigmatropic shift
- (c) [3, 3]-sigmatropic shift
- (d) Pummerer rearrangement
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Answer: (b)
Q21 · Dec 2017 · 2 marks
The following reaction involves 
- (a) [1, 2] sigmatropic rearrangement
- (b) [2, 3] sigmatropic rearrangement
- (c) [3, 3] sigmatropic rearrangement
- (d) C-H insertion reaction
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Answer: (b)
Q22 · June 2016 · 2 marks
The major products A and B formed in the following reaction sequence are 
- (a)
- (b)
- (c)
- (d)
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Answer: (c)
Q23 · June 2016 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q24 · June 2016 · 2 marks
The major product formed in the following reaction sequence is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (c)
Q25 · June 2016 · 2 marks
The correct reagent combination to effect the following reaction is: 
- (a) (i) \mathrm{NaBH}_{4}, \mathrm{CeCl}_{3}, \mathrm{MeOH}, 0^{\circ} \mathrm{C} (ii) \mathrm{H}_{2},\left[\operatorname{Ir}(\mathrm{COD})(\mathrm{py}) \mathrm{P}(\mathrm{Cy})_{3}\left[\mathrm{PF}_{6}\right]\right. (iii) \mathrm{Ph}_{3} \mathrm{P}, \mathrm{PhCO}_{2} \mathrm{H}, \mathrm{DEAD} (iv) \mathrm{LiAlH}_{4}
- (b) i) Li, liquid \mathrm{NH}_{3} ii) \mathrm{H}_{2},\left[\operatorname{Ir}[\mathrm{COD})(\mathrm{py}) \mathrm{P}(\mathrm{Cy})_{3}\right] \mathrm{PF}_{6} iii) \mathrm{Ph}_{3} \mathrm{P}, \mathrm{PhCO}_{2} \mathrm{H}, \mathrm{DEAD} iv) \mathrm{NaBH}_{4}, \mathrm{CeCl}_{3}, \mathrm{MeOH}, 0^{\circ} \mathrm{C}
- (c) i) \mathrm{H}_{2}, \mathrm{Pd} / \mathrm{C} ii) \mathrm{LiAlH}_{4},-78^{\circ} \mathrm{C}
- (d) i) \mathrm{H}_{2}, Pd/C ii) Li , liquid \mathrm{NH}_{3}
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Answer: (a)
Q26 · Dec 2016 · 2 marks
The most stable product formed in the following reaction is 
- (a)
- (b)
- (c)
- (d)
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Answer: (a)
Q27 · Dec 2016 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (c)
Q28 · Dec 2016 · 2 marks
The major product in the following reaction is 
- (a)
- (b)
- (c)
- (d)
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Answer: (a)
Q29 · June 2016 · 2 marks
The frontier orbital interactions involved in the formation of the carbocation intermediate in the reaction of isobutylene with HCl are
- (a) \pi of olefin and \sigma^* of HCl
- (b) \pi of olefin and \sigma of HCl
- (c) \pi^* of olefin and \sigma^* of HCl
- (d) \pi^* of olefin and \sigma of HCl
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Answer: (a)
Q30 · June 2016 · 2 marks
The following transformation proceeds through two consecutive electrocyclic processes, which are 
- (a) 4 \pi conrotatory and 6 \pi conrotatory
- (b) 4 \pi disrotatory and 6 \pi conrotatory
- (c) 4 \pi conrotatory and 6 \pi disrotatory
- (d) 4 \pi disrotatory and 6 \pi disrotatory
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Answer: (c)
Q31 · Dec 2016 · 2 marks
The correct sequence of pericyclic reactions involved in the following transformation is 
- (a) (i) ene reaction, (ii) [2,3]-sigmatropic shift, (iii) [3,3]-sigmatropic shift
- (b) (i) ene reaction, (ii) [3,3]-sigmatropic shift, (iii) [1,3]-sigmatropic shift
- (c) (i) [2,3]-sigmatropic shift, (ii) ene reaction, (iii) [1,3]-sigmatropic shift
- (d) (i) [1,3]-sigmatropic shift, (ii) [2,3]-sigmatropic shift, (iii) [3,3]-sigmatropic shift
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Answer: (a)
Q32 · June 2015 · 2 marks
The major product formed in the following reaction is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q33 · June 2015 · 2 marks
The major product formed in following reaction is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q34 · June 2015 · 2 marks
The structures of A and B in the following reaction sequence are 
- (a)
- (b)
- (c)
A = - (d)
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Answer: (b)
Q35 · Dec 2015 · 2 marks
The major product formed in the following reaction is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q36 · Dec 2015 · 2 marks
The major product formed in the following reaction sequence is: 
- (a)
- (b)
- (c)
- (d)
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Answer: (d)
Q37 · Dec 2015 · 2 marks
The major structures of A and B in the following reaction sequence are 
- (a)
- (b)
- (c)
A = 
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Answer: (c)
Q38 · Dec 2015 · 2 marks
The major structures of A and B in the following reaction sequence are 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q39 · Dec 2015 · 2 marks
The major structures of A and B in the following reaction sequence are 
- (a)
- (b)
- (c)
- (d)
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Answer: (a)
Q40 · Dec 2015 · 2 marks
The major product formed by photochemical reaction of (2E, 4Z, 6E)-decatriene is
- (a)
- (b)
- (c)
- (d)
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Answer: (a)
Q41 · Dec 2014 · 2 marks
The major product of the following reaction is
- (a)
- (b)
- (c)
- (d)
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Answer: (c)
Q42 · June 2014 · 2 marks
The products A and B in the following reaction sequence are: 
- (a)
- (b)
A = - (c)
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Answer: (a)
Q43 · June 2014 · 2 marks
The products A and B in the following reaction sequence are: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q44 · Dec 2014 · 2 marks
The major product formed in the following reaction sequence is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (c)
Q45 · Dec 2014 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q46 · Dec 2014 · 2 marks
The products A and B in the following reaction sequence are: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q47 · Dec 2014 · 2 marks
The products A and B in the following reaction sequence are: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q48 · Dec 2014 · 2 marks
The major product of the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (d)
Q49 · Dec 2014 · 2 marks
The products A and B in the following reaction sequence are 
- (a)
- (b)
- (c)
- (d)
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Answer: (c)
Q50 · June 2014 · 2 marks
In a Diels-Alder reaction, the most reactive diene amongst the following is
- (a) (4E)-1, 4-hexadiene
- (b) (4Z)-1, 4-hexadiene
- (c) (2E, 4E)-2, 4-hexadiene
- (d) (2Z, 4Z)-2, 4-hexadiene
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Answer: (c)
Q51 · June 2014 · 2 marks
Pericyclic reaction involved in one of the steps of the following reaction sequence is 
- (a) [1, 3] sigmatropic shift
- (b) [3, 3] sigmatropic shift
- (c) [1, 5] sigmatropic shift
- (d) [2, 3] sigmatropic shift
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Answer: (d)
Q52 · June 2013 · 2 marks
The major product formed in the following reaction is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (c)
Q53 · June 2013 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q54 · June 2013 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q55 · Dec 2013 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (c)
Q56 · Dec 2013 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (d)
Q57 · Dec 2013 · 2 marks
The major product formed in the following reaction sequence is:
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (d)
Q58 · Dec 2013 · 2 marks
In the following transformation, the reagent A and the major product B , respectively, are 
and 
and - (a)
and - (b)
and - (c)
and - (d)
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Answer: (d)
Q59 · Dec 2013 · 2 marks
The major product formed in the following reaction sequence is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q60 · Dec 2013 · 2 marks
The major product formed in the following reaction sequence is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q61 · June 2012 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (d)
Q62 · June 2012 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q63 · June 2012 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q64 · Dec 2012 · 2 marks
The major product formed in the following reaction is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (c)
Q65 · Dec 2012 · 2 marks
The major product formed in the following reaction sequence is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q66 · Dec 2012 · 2 marks
The major product B formed in the following reaction sequence is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q67 · Dec 2012 · 2 marks
The major product B formed in the following reaction sequence is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q68 · Dec 2012 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q69 · Dec 2012 · 2 marks
The following transformation involves
- (a) an iminium ion, [3, 3]-sigmatropic shift and Mannich reaction.
- (b) a nitrenium ion, [3, 3]-sigmatropic shift and Michael reaction.
- (c) an iminium ion, [1, 3]-sigmatropic shift and Mannich reaction.
- (d) a nitrenium ion, [1,3]-sigmatropic shift and Michael reaction.
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Answer: (a)
Q70 · Dec 2011 · 2 marks
The major products A and B in the following reaction sequence are 
- (a)
- (b)
A = B = - (c)
B = - (d)
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Answer: (b)
Q71 · June 2011 · 2 marks
Show answer
Answer: (d)
Q72 · June 2011 · 2 marks
The major product formed in the following reaction is:
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (c)
Q73 · June 2011 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q74 · June 2011 · 2 marks
The major product formed in the following reaction is: 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (b)
Q75 · Dec 2011 · 2 marks
The major product formed in the following reaction is 
- (a)
- (b)
- (c)
- (d)
Show answer
Answer: (a)
Q76 · Dec 2011 · 2 marks
The major products A and B in the following reaction sequence are 
- (a)
- (b)
A = - (c)
- (d)
Show answer
Answer: (b)
Q77 · Dec 2011 · 2 marks
In the following concerted reaction, the product is formed by a 
- (a) 6 \pi - disrotatory electrocyclisation
- (b) 4 \pi - disrotatory electrocyclisation
- (c) 6 \pi - conrotatory electrocyclisation
- (d) 4 \pi - conrotatory electrocyclisation
Show answer
Answer: (a)
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