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प्रश्न
Explain primary benzylic halide shows higher reactivity by SN1 mechanism than other primary alkyl halide.
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उत्तर
- SN1 reaction involves the formation of a carbocation intermediate. The benzylic carbocation intermediate formed are resonance stabilized, and hence SN1 mechanism is favoured.
- Resonance stabilization of benzylic carbocation can be represented as:
- Reactivity order of alkyl halides towards SN1 mechanism is 3° > 2° > 1° > CH3X. That is, SN1 mechanism is least favoured in primary alkyl halides.
- Benzylic carbocation formed is more stable than the primary carbocation; therefore, primary benzylic halide shows higher reactivity by SN1 mechanism than other primary alkyl halide.
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संबंधित प्रश्न
Complete the following reaction giving major products.
Name the reagent used to bring about the following conversion.
Ethyl bromide to ethyl isocyanide
Arrange the following in the increasing order of boiling points.
- 1-Bromopropane
- 2- Bromopropane
- 1- Bromobutane
- 1-Bromo-2-methylpropane
Convert the following:
Propene to propan-1-ol
HCl is added to a hydrocarbon ‘A’ \[\ce{(C4H8)}\] to give a compound ‘B’ which on hydrolysis with aqueous alkali forms tertiary alcohol ‘C’ \[\ce{(C4H10O)}\]. Identify ‘A’ ,‘B’ and ‘C’.
Observe the following and answer the question given below.
Comment on the bond length of C–X bond in it.
The following will react faster by SN1 mechanism
Major product of the following reaction is _______________
\[\ce{CH3-CH2-Mg-Br + NH3 ->?}\]
Write the correct order of increasing ease of dehydrohalogenation.
\[\ce{\underset{\text{(I)}}{CH3 - CH2 - CH2 - Cl}}\]
\[\ce{\underset{\text{(II)}}{CH3 - CH(Cl) - CH3}}\]
\[\begin{array}{cc}
\ce{CH3}\\
|\\
\ce{CH3-C-Cl}\phantom{...}\\
|\\
\ce{CH3}\\
\ce{(III)}
\end{array}\]
Explain. Aryl halides are less reactive than alkyl halides towards nucleophilic substitution reactions.
Explain aqueous alkaline hydrolysis of tert. butyl bromide.
What is dehydrohalogenation? State the rule for the formation of the preferred product of dehydrohalogenation.
Which of the following is a primary halide?
Ethyl bromide undergoes the following reaction:
\[\ce{\underset{Ethyl bromide}{C2H5Br} + \underset{(aq.)}{KOH} ->[\Delta] \underset{Ethyl alcohol}{C2H5OH} + KBr}\]
Which of the following is a WRONG statement?
How many metameric ethers are represented by the molecular formula C4H10O?
When C2H5Br is treated with excess of alc. NH3, the major product obtained is ____________.
Write the product formed when alkyl halide reacts with silver nitrite.
Which among the following statements is not correct about SN2 reaction mechanism?
Complete the following reaction giving major products.
\[\begin{array}{cc}
\ce{CH3}\phantom{.......}\\
|\phantom{.........}\\
\ce{CH3 - c - CH2 - Cl ->[Na/dry ether]}\\
|\phantom{.........}\\
\ce{CH3}\phantom{.......}
\end{array}\]
Complete the following reaction giving a major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{.................}\\
|\phantom{...................}\\
\ce{CH3 - C - CH2 - Cl->[Na/dry ether]A}\\
|\phantom{..................}\\
\ce{CH3}\phantom{................}
\end{array}\]
Discuss β - elimination reaction.
Complete the following reaction sequences by writing the structural formulae of the organic compounds 'A', 'B' and 'C'.
\[\ce{2-Bromobutan ->[alc. KOH] A ->[][Br2] B ->[][NANH2] C}\]
Complete the following reactions giving major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{................}\\
|\phantom{...................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether] A}\\
|\phantom{...................}\\
\ce{CH3}\phantom{.................}
\end{array}\]
What is the action of following on ethyl bromide?
alcoholic sodium hydroxide
Complete the following reaction giving major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{...............}\\
|\phantom{..................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether]A}\\
|\phantom{...................}\\
\ce{CH3}\phantom{.................}
\end{array}\]
Complete the following reaction giving major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{................}\\
|\phantom{..................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether]A}\\
|\phantom{..................}\\
\ce{CH3}\phantom{................}
\end{array}\]
Complete the following reaction giving major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{................}\\
|\phantom{...................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether] A}\\
|\phantom{...................}\\
\ce{CH3}\phantom{................}\\
\end{array}\]
