Q1 · 2000-2022 · 2 marks
Order of reactivity of the following dienes X, Y and Z in Diels–Alder reaction is (X) (Y) (Z)
- (a) X>Z>Y
- (b)
Y>X>Z - (c)
Y>Z>X - (d) X>Y>Z
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Answer: (a)
GATE Chemistry (CY) — Reagents, Named and Pericyclic Reactions previous year questions
27 questions · 2000 · all with verified answer · last checked 2026-11-11
Q2 · 2000-2022 · 2 marks
The major product P of the given reaction is 
- (a)
- (b)
- (c)
- (d)
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Answer: (d)
Q3 · 2000-2022 · 2 marks
The major product P formed in the following photochemical reactionis 
- (a)
- (b)
- (c)
- (d)
GATE-2006
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Answer: (b)
Q4 · 2000-2022 · 2 marks
Identify the major product P and Q in the following reactions from the list of compounds I to IV. 
- (a)
P:I and Q:II - (b)
P:II and Q:III - (c)
P:IV and Q:II - (d)
P:IV and Q:III
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Answer: (c)
Q5 · 2000-2022 · 2 marks
The reaction between X and Y to give Z proceeds via 
- (a) 4 \pi-conrotatory opening of X followed by endo Diels - Alder cycloaddition.
- (b) 4 \pi-disrotatory opening of X followed by endo Diels - Alder cycloaddition.
- (c) 4 \pi-conrotatory opening of X followed by exo Diels - Alder cycloaddition.
- (d) 4 \pi-disrotatory opening of X followed by exo Diels - Alder cycloaddition.
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Answer: (b)
Q6 · 2000-2022 · 2 marks
In the reaction, 
the major product [X] is:
the major product [X] is: - (a)
- (b)
- (c)
- (d)
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Answer: (c)
Q7 · 2000-2022 · 2 marks
The diene which undergoes Diels-Alder reaction with maleic anhydride is:
- (a)
- (b)
- (c)
- (d)
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Answer: (b)
Q8 · 2000-2022 · 2 marks
In the following reaction, the major product [X] is:
- (a)
- (b)
- (c)
- (d)
GATE-2012
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Answer: (a)
Q9 · 2000-2022 · 2 marks
The pericyclic reaction given below is an example of
- (a) [1,3]–sigmatropic shift
- (b)
[1,5]–sigmatropic shift - (c) [3,5]–sigmatropic shift
- (d) [3,3]–sigmatropic shift
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Answer: (b)
Q10 · 2000-2022 · 2 marks
The major product X and Y formed in the following reaction sequence are cis - stilbene \xrightarrow[\mathrm{C}_{6} \mathrm{H}_{12}]{\mathrm{hv}} \xrightarrow[\text { air }]{\mathrm{I}_{2}} \mathrm{Y} 
- (a) \mathrm{X}=
- (b) \mathrm{X}=
Y= - (c)
\mathrm{X}= \mathrm{Y}= - (d) \mathrm{X}=
\mathrm{Y}= GATE-2015
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Answer: (a)
Q11 · 2000-2022 · 2 marks
In the two setp reaction sequence given below, the starting bis - sulfone acts as 
- (a) a dienophile and synthetic equivalent of acetylene
- (b) a dienophile and synthetic equivalent of ethylene
- (c) a dipolarophile and synthetic equivalent of acetylene
- (d) a dipolarophile and synthetic equivalent of ethylene
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Answer: (d)
Q12 · 2000-2022 · 2 marks
The result of the reduction of either (R) or (S) 2-methylcyclohexanone, in separate reactions, using \mathrm{LiAlH}_{4} is that the reduction of
- (a) The R enantiomer is stereoselective
- (b) The R enantiomer is stereospecific
- (c) The S enantiomer is stereospecific
- (d) Both the R and S enantiomers is stereoselective
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Answer: (d)
Q13 · 2000-2022 · 2 marks
In the reaction sequence 
the major product respectively, are: 
the major product respectively, are: - (a)
and - (b)
and - (c)
and - (d)
and
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Answer: (a)
Q14 · 2000-2022 · 2 marks
In the reaction sequence the major products X and Y , respectively are 
- (a)
and - (b)
and - (c)
and - (d)
and GATE-2010
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Answer: (c)
Q15 · 2000-2022 · 2 marks
In the reaction, 
the major products, [\mathrm{X}] and [\mathrm{Y}], respectively, are 
the major products, [\mathrm{X}] and [\mathrm{Y}], respectively, are - (a)
and - (b)
and - (c)
and - (d)
and
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Answer: (b)
Q16 · 2000-2022 · 2 marks
In the reaction sequence 
the major products, [\mathrm{X}] and [\mathrm{Y}] respectively, are 
the major products, [\mathrm{X}] and [\mathrm{Y}] respectively, are - (a)
and - (b)
and - (c)
and - (d)
and GATE-2011
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Answer: (c)
Q17 · 2000-2022 · 2 marks
In the following reaction 
the major product [\mathrm{X}] is:
the major product [\mathrm{X}] is: - (a)
(i) Peracid; (ii) \mathrm{H}^{+}; (iii) \mathrm{Zn} / \mathrm{dil} . \mathrm{HCl} - (b)
(i) Alkaline \mathrm{KMnO}_{4}; (ii) \mathrm{NaIO}_{4}; (iii) \mathrm{N}_{2} \mathrm{H}_{4} / \mathrm{KOH} - (c)
(i) Alkaline \mathrm{KMnO}_{4}; (ii) \mathrm{H}^{+}; (iii) \mathrm{Zn} / dil. HCl - (d)
is (i) \mathrm{O}_{2} / \mathrm{Me}{ }_{2} \mathrm{~S}; (ii) NaOEt ; (iii) \mathrm{N}_{2} \mathrm{H}_{4} / \mathrm{KOH}
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Answer: (c)
Q18 · 2000-2022 · 2 marks
The most appropriate sequence of reactions for carrying out the following conversion 
is
is - (a) (i) Peracid; (ii) \mathrm{H}^{+}; (iii) \mathrm{Zn}/\text{dil.}\ \mathrm{HCl}
- (b) (i) Alkaline \mathrm{KMnO}_{4}; (ii) \mathrm{NaIO}_{4}; (iii) \mathrm{N}_{2}\mathrm{H}_{4}/\mathrm{KOH}
- (c) (i) Alkaline \mathrm{KMnO}_{4}; (ii) \mathrm{H}^{+}; (iii) \mathrm{Zn}/\text{dil.}\ \mathrm{HCl}
- (d) (i) \mathrm{O}_{3}/\mathrm{Me}_{2}\mathrm{S}; (ii) \mathrm{NaOEt}; (iii) \mathrm{N}_{2}\mathrm{H}_{4}/\mathrm{KOH}
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Answer: (d)
Q19 · 2000-2022 · 2 marks
Identify the product from the following reaction 
- (a)
- (b)
- (c)
- (d)
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Answer: (a)
Q20 · 2000-2022 · 2 marks
The overall yield (in \%) for the following reaction sequence is 
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Answer: 57.6
Q21 · 2000-2022 · 2 marks
The most suitable reagent combination to effect the following conversion is 
- (a) (i) \mathrm{NaH}, \mathrm{CS}_{2}, then MeI; (ii) \mathrm{Bu}_{3} \mathrm{SnH}, \mathrm{AlBN}, \mathrm{C}_{6} \mathrm{H}_{6}, Reflux
- (b) (i) \mathrm{I}_{2}, \mathrm{PPh}_{3}, imidazole; (ii) \mathrm{H}_{2}, 10 \% \mathrm{Pd}-\mathrm{C}, \mathrm{AcOH}, high pressure
- (c) (i) \mathrm{Me}_{3} \mathrm{SiCl}, pyridine, DMAP; (ii) \mathrm{Bu}_{3} \mathrm{SnH}, \mathrm{AlBN}, \mathrm{C}_{6} \mathrm{H}_{6}, reflux
- (d) (i) MsCl , pyridine, DMAP ; (ii) \mathrm{LiAlH}_{4}, \mathrm{THF}, reflux
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Answer: (a)
Q22 · 2000-2022 · 2 marks
The mass spectrum of a dihalo compound shows peaks with relative intensities of 1:2:1 corresponding to \mathrm{M}, \mathrm{M}+2 and \mathrm{M}+4 (\mathrm{M} is the mass of the molecular ion), respectively. The compound is
- (a)
- (b)
- (c)
- (d)
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Answer: (a)
Q23 · 2000-2022 · 2 marks
For the following three alkenes, 1,2 , and 3 , the rates of hydrogeneation using Wilkinson's catalyst at 20^{\circ} \mathrm{C} vary in the order 1 2 3
- (a) 1>3>2
- (b)
1>2>3 - (c)
2>1>3 - (d)
2>3>1
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Answer: (b)
Q24 · 2000-2022 · 2 marks
Hydroboration of 2 - butyne with \left(\mathrm{C}_{6} \mathrm{H}_{11}\right)_{2} \mathrm{BH} yields the intermediate U , which on treatment with \mathrm{I}_{2} and NaOMe at -78^{\circ} \mathrm{C}, gives product V. The structure of U and V are 
- (a) \mathrm{U}=
\mathrm{V}= - (b) \mathrm{U}=
V = - (c) \mathrm{U}=
\mathrm{V}= - (d)
V =
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Answer: (d)
Q25 · 2000-2022 · 2 marks
The major product formed in the following reaction sequence is 
- (a)
- (b)
- (c)
- (d)
GATE-2019
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Answer: (d)
Q26 · 2000-2022 · 2 marks
Character table of point group \mathrm{D}_{8} is given below
Value of (a+b+c+d+e+f+g+h+i+j+k) is equal to ____
| \mathrm{D}_{8} | E | 2 \mathrm{C}_{8} | 2 \mathrm{C}_{4} | 2 \mathrm{C}_{8}^{3} | \mathrm{C}_{2} | 4 \mathrm{C}_{2}^{\prime} | 4 \mathrm{C}_{2}^{\prime \prime} |
| \mathrm{A}_{1} | a | 1 | 1 | 1 | 1 | 1 | 1 |
| \mathrm{A}_{2} | b | 1 | 1 | 1 | 1 | h | i |
| B { }_{1} | c | -1 | 1 | -1 | 1 | 1 | j |
| B { }_{2} | d | -1 | 1 | -1 | 1 | -1 | 1 |
| \mathrm{E}_{1} | e | \sqrt{2} | 0 | -\sqrt{2} | -2 | 0 | 0 |
| \mathrm{E}_{2} | f | 0 | -2 | 0 | k | 0 | 0 |
| \mathrm{E}_{3} | g | -\sqrt{2} | 0 | \sqrt{2} | -2 | 0 | 0 |
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Answer: 9
Q27 · 2000-2022 · 2 marks
Major product formed in the following synthetic sequence is: 
- (a)
- (b)
- (c)
- (d)
GATE-2021
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Answer: (a)
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