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प्रश्न
Arrange the compounds of the following set in order of reactivity towards SN2 displacement:
1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 2-Bromo-3-methylbutane
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उत्तर
The SN2 reaction involves the formation of a transition state with the carbon atom surrounded by 5 additional atoms (groups). A transition state requires minimum steric interactions. The most suitable substrates for SN2 reactions are 1° alkyl halides, followed by 2° and 3° alkyl halides. The order of reactivity towards SN2 is 1° > 2° > 3°> aryl halide. Based on this, the order will be
\[\begin{array}{cc}
\ce{CH3}\phantom{...............................}\ce{CH3}\phantom{.................}\ce{CH3}\phantom{.....}\\
\phantom{.....}|\phantom{...................................}|\phantom{....................}|\phantom{............}\\
\ce{\underset{1-Bromo-3-methylbutane}{H3C - CH - CH2 - CH2Br} > \ce{CH3 - CH - CH - CH3} > \ce{CH3 - C - CH2 - CH3}}\\
\phantom{.......................}|\phantom{..........................}|\\
\phantom{.........................}\ce{\underset{2-Bromo-3-methylbutane}{Br}\phantom{.........}\ce{\underset{2-Bromo-2-methylbutane}{Br}}}\
\end{array}\]
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संबंधित प्रश्न
In the following pair of halogen compounds, which compound undergoes a faster SN1 reaction?
Out of C6H5CH2Cl and C6H5CHClC6H5, which is more easily hydrolysed by aqueous KOH.
C–Cl bond length in chlorobenzene is shorter than C–Cl bond length in CH3–Cl.
Given reasons: SN1 reactions are accompanied by racemization in optically active alkyl halides.
Identify 'A' in the following reaction -
(a) 2- Bromo-2 methylbutane
(b) 1 -Bromo-2,2-dimethylpropane
(c) 1 - Bromo - 3 -methylbutane
(d) 1 - Bromo- 2 -methylpropane
What is the action of the following on ethyl bromide:
moist silver oxide
The order of reactivity of the given haloalkanes towards nucleophile is:
Most reactive halide towards SN1 reaction is ____________.
Optically active isomers but not mirror images are called ____________.
The process of separation of a racemic modification into d and l-enantiomers is called ____________.
2-Bromopentane is heated with potassium ethoxide in ethanol. The major product obtained is ____________.
The increasing order of reactivity towards SN1 mechanism is:
(I) \[\begin{array}{cc}
\ce{CH3-CH-CH2-CH3}\\
|\phantom{........}\\
\ce{CH3}\phantom{.....}
\end{array}\]
(II) CH3CH2CH2Cl
(III) P–CH3O–C6H4–CH2Cl
Which of the statements are correct about above reaction?
(i) (a) and (e) both are nucleophiles.
(ii) In (c) carbon atom is sp3 hybridised.
(iii) In (c) carbon atom is sp2 hybridised.
(iv) (a) and (e) both are electrophiles.
Which of the following statements are correct about this reaction?
(i) The given reaction follows SN2 mechanism.
(ii) (b) and (d) have opposite configuration.
(iii) (b) and (d) have same configuration.
(iv) The given reaction follows SN1 mechanism.
How do polar solvents help in the first step in SN1 mechanism?
Elimination reactions (especially β-elimination) are as common as the nucleophilic substitution reaction in case of alkyl halides. Specify the reagents used in both cases.
Among the following compounds I - IV, which one forms a yellow precipitate on reacting sequentially with (i) NaOH (ii) dil. HNO3 (iii) AgNO3?
 |
 |
 |
 |
| I | II | III | IV |
Optical activity of an enantiomeric mixture is +12.6° and the specific rotation of (+) isomer is +30°. The optical purity is ______ %.
HCI, Major product ______.
The correct order of increasing reactivity of
C-X bond towards nucleophile in the following compounds is:
