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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
Arrange the following in the increasing order of boiling points.
- 1-Bromopropane
- 2- Bromopropane
- 1- Bromobutane
- 1-Bromo-2-methylpropane
Give reasons:
Haloarenes are less reactive than haloalkanes.
Convert the following:
Ethanol to propane nitrile
Convert the following:
2-Chloropropane to propan-1-ol
Convert the following:
tert-Butyl bromide to isobutyl bromide
Complete the following reaction sequence by writing the structural formulae of the organic compound 'A', 'B' and 'C'.
\[\ce{2-Bromobutane->[Alc.KOH]A->[][Br2]B->[][NaNH2]C}\]
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 is a primary halide?
Dehydrohalogenation of an alkyl halide is ____________.
Nitroalkanes are obtained in laboratory from primary or secondary alkyl halides by the action of ______.
What type of hybridisation is present in carbocation formed during the alkaline hydrolysis of 1- bromo-1- phenyl ethane?
\[\ce{C6H5CH2Cl + KCN(alc) -> X + Y}\]
Compounds X and Y are ____________.
When C2H5Br is treated with excess of alc. NH3, the major product obtained is ____________.
Identify 'B' in the following reaction.
\[\ce{2-Bromobutane ->[KOH alc.][\Delta] A ->[HI] B}\]
What is the major product obtained in the sulphonation of chlorobenzene with concentrated sulphuric acid?
The order of reactivities of the following alkyl halides for an SN2 reaction is ______.
Complete the following reactions giving a major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{................}\\
|\phantom{..................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether] A}\\
|\phantom{..................}\\
\ce{CH3}\phantom{................}
\end{array}\]
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 question given below:
Can react by SN1 mechanism? Justify your answer.
Complete the following reactions giving major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{................}\\
|\phantom{...................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether] A}\\
|\phantom{...................}\\
\ce{CH3}\phantom{.................}
\end{array}\]
Identify the chiral molecule from the following.
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.
