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प्रश्न
Elimination reactions (especially β-elimination) are as common as the nucleophilic substitution reaction in case of alkyl halides. Specify the reagents used in both cases.
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उत्तर
Alkyl halides undergo nucleophilic substitution as well as elimination (Beta-elimination) reaction. However, by proper choice of reagents and reaction conditions, a particular product can be obtained. Usually strong and bulky bases and high temperature favour elimination reactions while weaker and smaller bases and lower temperature favour substitution reactions. For example, ethyl bromide on heating with alcoholic KOH (which contain stronger base, \[\ce{C2H5O}\] ion) at about 473-523 K undergoes elimination to give ethene. But with aqueous \[\ce{KOH}\] at about 373 K, it gives ethanol.
\[\ce{CH3CH2Br ->[alc.KOH][473-523 K] CH2 = CH2 (Elimination)}\]
\[\ce{CH3CH2Br ->[aq.KOH][373 K] CH3CH2OH (Substitution)}\]
Nucleophilic substitution: Reagents used nucleophilies like \[\ce{- \overset{-}{O}H, NH3, \overset{-}{C} ≡ N;, AgCN:, O = N - O, \overset{-}{O}R}\]' etc. also, alc. \[\ce{KOH}\] at lower temperature (373 K) undergoes substitution reaction.
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संबंधित प्रश्न
Write the major products(s) in the following:
Out of 
, which is more reactive towards SN1 reaction and why?
Which compound in the following pair will react faster in SN2 reaction with OH−?
CH3Br or CH3I
What happens when ethyl chloride is treated with aqueous KOH?
How the following conversion can be carried out?
Ethyl chloride to propanoic acid.
Arrange the following organic compounds in descending order of their reactivity towards SN1 reaction.
C6H5CH2Br, C6H5CH(C6H5)Br, C6H5CH(CH3)Br, C6H5C(CH3)(C6H5)Br
Which one of the following halogen compounds is difficult to be hydrolysed by SN1 mechanism?
In the SN1 reaction, racemization takes place. It is due to:
An important chemical method to resolve a racemic mixture makes use of the formation of ______.
SN1 reaction of alkyl halides lead to ___________.
The increasing order of nucleophilicity would be:
The correct order of increasing the reactivity of C–X bond towards nucleophile in following compounds.
(I)
(II)
(CH3)3CCl
(III)
(CH3)2CHCl
(IV)
Cyanide ion acts as an ambident nucleophile. From which end it acts as a stronger nucleophile in aqueous medium? Give reason for your answer.
In SN1 reactions, the correct order of reactivity for the following compounds:
CH3Cl, CH3CH2Cl, (CH3)2CHCl and (CH3)3CCl is ______.
Inversion of configuration occurs in ______.
Identify the product in the following reaction: 
Discuss SN2 mechanism of methyl bromide using aqueous KOH.
Which one of the following chlorohydrocarbons readily undergoes solvolysis?
HCI, Major product ______.
