Electronic Effects, Stereochemistry and Aromaticity - Structure-Reactivity Correlations and Organic Reaction Mechanisms - Life Sciences Previous Year Questions

1

2007 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2007

The most stable conformation of cis-1-tert-butyl-4-methylcyclohexane is

A

B

C

D

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2

2008 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2008

Among the following four amines, which one is least basic in aqueous solution?

A

\(CH_3NH_2\)

B

\((CH_3)_2NH\)

C

\((CH_3)_3N\)

D

\(CH_3NHCH_2CH_3\)

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3

2008 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2008

The reactivity order for nitration of benzene, chlorobenzene, phenol and nitrobenzene is

A

Benzene > Chlorobenzene > Phenol > Nitrobenzene

B

Phenol > Benzene > Chlorobenzene > Nitrobenzene

C

Nitrobenzene > Phenol > Chlorobenzene > Benzene

D

Phenol > Chlorobenzene > Benzene > Nitrobenzene

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4

2009 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2009

The most stable carbocation among the following is

A

\(CH_3OCH_2CH_2^+ \)

B

\(CH_3CH=CHCH_2^+ \)

C

\(CH_3CH_2^+ \)

D

\(H_3C-C(=O)-CH_2^+ \)

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5

2009 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2009

The carboxylic acid with the lowest \( pK_a \) value is

A

\(C_6H_5CO_2H \)

B

\(CH_3CO_2H \)

C

\(p-CH_3O-C_6H_4CO_2H \)

D

\(p-CH_3-C_6H_4CO_2H \)

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6

2009 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2009

The major product formed in the nitration of \( o \)-methoxybenzoic acid is

A

Option A: compound with CO2H and OCH3 on adjacent positions, NO2 at para to OCH3

B

Option B: compound with CO2H and OCH3 on adjacent positions, NO2 at meta to OCH3

C

Option C: compound with CO2H and OCH3 on adjacent positions, NO2 at ortho to OCH3

D

Option D: compound with CO2H and OCH3 on adjacent positions, NO2 at ortho to CO2H

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7

2009 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2009

Which one of the following Fischer projections represents \( (S,S) \)-tartaric acid ?

A

Fischer projection with OH on left and right, H on left and right

B

Fischer projection with OH on right and right, H on left and left

C

Fischer projection with OH on left and left, H on right and right

D

Fischer projection with OH on right and left, H on right and left

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8

2009 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2009

Which one among the following compounds loses a proton most readily in a basic medium ?

A

Cyclopentadiene

B

Cycloheptatriene

C

Cyclopropene

D

1,3-Cyclohexadiene

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9

2010 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2010

Among heptan-1-ol, heptan-2-ol, heptan-3-ol and heptan-4-ol, compounds those exhibit optical activity are

A

heptan-2-ol and heptan-3-ol

B

heptan-2-ol and heptan-4-ol

C

heptan-3-ol and heptan-4-ol

D

heptan-1-ol and heptan-4-ol

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10

2011 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2011

Electrophile among the following is

A

NH3

B

SO3

C

NO2

D

CH≡C⁻

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11

2011 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2011

The correct order of acidity is

A

C₂H₅COOH < CH₃COOH < C₆H₅OH < C₂H₅OH

B

CH₃COOH < C₆H₅COOH < C₆H₅OH < C₂H₅OH

C

C₆H₅OH < C₆H₅OH < CH₃COOH < C₆H₅COOH

D

C₂H₅OH < C₆H₅OH < CH₃COOH < C₆H₅COOH

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12

2012 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2012

Among the following, the most reactive diene in the Diels-Alder reaction is

A

1-methylcyclohexa-1,3-diene

B

Buta-1,3-diene

C

Furan

D

Cyclopenta-1,3-diene

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13

2012 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2012

The non-aromatic compound/ion is

A

Cyclooctatetraene

B

Cyclopentadienyl cation

C

Cyclooctatetraenyl dianion

D

Cyclopentadienyl anion

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14

2013 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2013

The absolute configuration of 1-chloro-3-ethylcyclopentane (\(\mathbf{X}\)) shown above is

A

(1S,3R)

B

(1S,3S)

C

(1R,3R)

D

(1R,3S)

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15

2014 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2014

The order of acidity of the following acids is

A

3 > 2 > 1 > 4

B

1 > 4 > 3 > 2

C

4 > 3 > 2 > 1

D

3 > 4 > 2 > 1

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16

2016 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2016

The total number of chair conformations possible for 1,2-dimethylcyclohexane is ____.

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17

2017 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2017

The correct order of stability in water is

A

MeCONMe₂ > MeCOOMe > MeCOOCOMe > MeCOCl

B

MeCOOMe > MeCONMe₂ > MeCOOCOMe > MeCOCl

C

MeCONMe₂ > MeCOOMe > MeCOCl > MeCOOCOMe

D

MeCONMe₂ > MeCOOCOMe > MeCOOMe > MeCOCl

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18

2018 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2018

The compound, which upon mono-nitration using a mixture of HNO₃ and H₂SO₄, does NOT give the meta-isomer as the major product, is

A

Toluene (CF₃ group)

B

Nitrobenzene (NO₂ group)

C

Acetanilide (NHCOCH₃ group)

D

Benzoic acid (COOH group)

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19

2018 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2018

The total number of possible stereoisomers for the compound with the structural formula CH₃CH(OH)CH=CHCH₂CH₃ is ______.

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20

2019 · Life Sciences · Structure-Reactivity Correlations and Organic Reaction Mechanisms · Electronic Effects, Stereochemistry and Aromaticity

Life Sciences (XL) 2019

The total number of tautomers for the following molecule (including the structure provided below) is ______.

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