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प्रश्न
Give reasons:
Haloarenes are less reactive than haloalkanes.
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उत्तर
- The low reactivity of aryl halides is due to resonance effect and sp2 hybrid state of carbon to which halogen atom is attached.
- In aryl halides, one of the lone pairs of electrons on halogen atom is in conjugation with π-electrons of the ring. Due to resonance, the C–X bond acquires partial double bond character. Thus, the C–X bond in haloarenes is stronger and shorter than haloalkanes. Hence, it is difficult to break C–X bond in haloarenes. (e.g. C–Cl bond length in chlorobenzene is 169 pm as compared to C–Cl bond length in alkyl chloride which is 178 pm).
Therefore, haloarenes are less reactive than haloalkanes.
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संबंधित प्रश्न
Complete the following reaction giving major products.
\[\ce{CH3 - CH = CH2 ->[HBr][peroxide] A ->[alc. KOH] B}\]
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 products.
Name the reagent used to bring about the following conversion.
Bromoethane to ethoxyethane
Name the reagent used to bring about the following conversion.
Chlorobenzene to biphenyl
Convert the following:
Benzyl alcohol to benzyl cyanide
Observe the following and answer the question given below.
Comment on the bond length of C–X bond in it.
Propane nitrile can be prepared by heating ____________
Nucleophilic substitution reaction of 2, 4-dinitrochlorobenzene is faster than p-nitrochlorobenzene. Give reason.
Explain the factors affecting SN1 and SN2 mechanism.
Explain aqueous alkaline hydrolysis of tert. butyl bromide.
Which of the following is least reactive towards nucleophilic addition?
\[\ce{C6H5CH2Cl + KCN(alc) -> X + Y}\]
Compounds X and Y are ____________.
Which of the following is FALSE regarding SN2 reaction mechanism?
When C2H5Br is treated with excess of alc. NH3, the major product obtained is ____________.
Convert the following.
p-Nitrochlorobenzene to p-nitrophenol
Explain the dehydrohalogenation reaction of 2-chlorobutane.
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 reactions giving a major product.
\[\begin{array}{cc}
\ce{CH3}\phantom{................}\\
|\phantom{..................}\\
\ce{CH3 - C - CH2 - Cl ->[Na/dry ether] A}\\
|\phantom{..................}\\
\ce{CH3}\phantom{................}
\end{array}\]
Observe the following and answer the question given below:
Comment on the bond length of C-X bond in it.
Observe the following and answer the question given below:
Can react by SN1 mechanism? Justify your answer.
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 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 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 among the following is NOT benzylic halide?
