Advertisements
Advertisements
प्रश्न
What is dehydrohalogenation? State the rule for the formation of the preferred product of dehydrohalogenation.
Advertisements
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?
a. CH3CH2CH2I b. CH3CH2CH2Cl
Complete the following reaction giving major products.
\[\ce{CH3 - CH = CH2 ->[HBr][peroxide] A ->[alc. KOH] B}\]
Complete the following reaction giving major products.
\[\begin{array}{cc}\ce{CH3 - CH = CH3 ->[Red P/Br2] A ->[Ag2O/H2O]B}\\|\phantom{.........................}\\
\ce{OH\phantom{.......................}}\end{array}\]
Name the reagent used to bring about the following conversion.
Bromoethane to ethoxyethane
Name the reagent used to bring about the following conversion.
Ethyl bromide to ethyl isocyanide
Give reasons:
Haloarenes are less reactive than haloalkanes.
Distinguish between SN1 and SN2 mechanism of substitution reaction.
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’.
Complete the following reaction sequence by writing the structural formulae of the organic compound 'A', 'B' and 'C'.
\[\ce{2-Bromobutane->[Alc.KOH]A->[][Br2]B->[][NaNH2]C}\]
Nucleophilic substitution reaction of 2, 4-dinitrochlorobenzene is faster than p-nitrochlorobenzene. Give reason.
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 primary benzylic halide shows higher reactivity by SN1 mechanism than other primary alkyl halide.
Which of the following carbocation is the most stable?
The SN2 reaction of a compound containing an asymmetric carbon atom always gives ____________.
Write the product formed when alkyl halide reacts with silver nitrite.
The major product formed when 2-bromobutane is treated with alcoholic KOH is ______.
Which among the following statements is not correct about SN2 reaction mechanism?
The compound that reacts the fastest with sodium methoxide is ______.
Explain the dehydrohalogenation reaction of 2-chlorobutane.
Observe the following and answer the question given below:
Can react by SN1 mechanism? Justify your answer.
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 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 pair of compounds on heating gives butanenitrile?
