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प्रश्न
What is dehydrohalogenation? State the rule for the formation of the preferred product of dehydrohalogenation.
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उत्तर
- Dehydrohalogenation reaction: When an alkyl halide having at least one β-hydrogen is boiled with an alcoholic solution of potassium hydroxide (KOH), it undergoes elimination of hydrogen atom from β-carbon and halogen atom from α-carbon resulting in the formation of an alkene. As hydrogen and halogen are removed in this reaction, it is termed a dehydrohalogenation reaction.
- Saytzeff’s rule:
Statement - “In dehydrohalogenation reaction, the preferred product is that alkene which has a greater number of alkyl groups attached to doubly bonded carbon atoms.”
संबंधित प्रश्न
from the following pair would undergo SN2 faster from the other?
from the following pair would undergo SN2 faster from the other?
a. CH3CH2CH2I b. CH3CH2CH2Cl
Complete the following reaction giving major products.
\[\begin{array}{cc}\ce{CH3 - CH = CH3 ->[Red P/Br2] A ->[Ag2O/H2O]B}\\|\phantom{.........................}\\
\ce{OH\phantom{.......................}}\end{array}\]
Complete the following reaction giving major products.
Name the reagent used to bring about the following conversion.
Ethyl bromide to ethyl isocyanide
Name the reagent used to bring about the following conversion.
Chlorobenzene to biphenyl
Distinguish between SN1 and SN2 mechanism of substitution reaction.
Convert the following:
Benzyl alcohol to benzyl cyanide
The following will react faster by SN1 mechanism
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 the factors affecting SN1 and SN2 mechanism.
In alkaline hydrolysis of tertiary butyl bromide, ____________.
The least reactive towards nucleophilic addition reactions is ____________.
Dehydrohalogenation of an alkyl halide is ____________.
The following mechanism has been proposed for the reaction of NO2 with F2 to form NO2F:
\[\ce{NO2_{(g)} + F2_{(g)} -> NO2F_{(g)} + F_{(g)} (slow)}\]
\[\ce{F_{(g)} + NO2_{(g)} -> NO2F_{(g)} (fast)}\]
The order of the reaction with respect to NO2(g)
Which of the following is FALSE regarding SN2 reaction mechanism?
When C2H5Br is treated with excess of alc. NH3, the major product obtained is ____________.
What is the major product obtained in the sulphonation of chlorobenzene with concentrated sulphuric acid?
Complete the following reaction giving a major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{.................}\\
|\phantom{...................}\\
\ce{CH3 - C - CH2 - Cl->[Na/dry ether]A}\\
|\phantom{..................}\\
\ce{CH3}\phantom{................}
\end{array}\]
Observe the following and answer the questions given below:
Name the type of halogen derivative.
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.
\[\begin{array}{cc}
\ce{CH3}\phantom{................}\\
|\phantom{...................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether] A}\\
|\phantom{...................}\\
\ce{CH3}\phantom{.................}
\end{array}\]
Complete the following reaction giving major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{...............}\\
|\phantom{..................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether]A}\\
|\phantom{...................}\\
\ce{CH3}\phantom{.................}
\end{array}\]
Give a reason for the following:
Ethoxy ethane with conc. HI at 373 K gives C2H5OH and CH3I but not CH3OH and C2H5I.
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.
\[\begin{array}{cc}
\ce{CH3}\phantom{................}\\
|\phantom{...................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether] A}\\
|\phantom{...................}\\
\ce{CH3}\phantom{................}\\
\end{array}\]
Which of the following reagent is used for conversion of alkyl halide into nitrile?
