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प्रश्न
Alkenes 
and carbonyl compounds 
, both contain a π bond but alkenes show electrophilic addition reactions whereas carbonyl compounds show nucleophilic addition reactions. Explain.
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उत्तर
Carbonyl group is polar in nature. Due to larger electronegativity of oxygen as compared to carbon, carbon acquires partial positive charge while O acquires partial negative charge.
Because of slight positive charge on C atom, it is attacked by nucleophiles and, therefore, undergoes nucleophilic addition reaction.
Ethylenic double bond is a non-polar bond and is a source of electrons. Therefore, it is attacked by electrophiles and undergoes electrophilic addition reactions.
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संबंधित प्रश्न
Acetaldehyde, when treated with which among the following reagents does NOT undergo addition reaction?
(A) Ammonia
(B) Hydroxylamine
(C) Ammoniacal silver nitrate
(D) Semicarbazide
Arrange the following in the increasing order of their reactivity towards nucleophilic addition reaction:
C6H5COCH3, CH3-CHO, CH3COCH3
Write the structures of the main products when acetone (CH3 − CO − CH3) reacts with the following reagent :
H2N − NHCONH2/H+
Write the products formed when CH3CHO reacts with the following reagents : HCN
Arrange the following compound in increasing order of its reactivity in nucleophilic addition reactions.
Ethanal, Propanal, Propanone, Butanone.
Hint: Consider steric effect and electronic effect.
Arrange the following compound in increasing order of its reactivity in nucleophilic addition reactions.
Benzaldehyde, p-Tolualdehyde, p-Nitrobenzaldehyde, Acetophenone.
Hint: Consider steric effect and electronic effect.
What is meant by the following term? Give an example of the reaction in the following case.
Imine
Acetaldehyde, Acetone, Di-tert-butyl ketone, Methyl tert-butyl ketone (reactivity towards HCN)
Give plausible explanation for the following:
There are two −NH2 groups in semicarbazide. However, only one is involved in the formation of semicarbazones.
Benzaldehyde can be obtained from benzal chloride. Write reactions for obtaining benzalchloride and then benzaldehyde from it.
Carboxylic acids contain carbonyl group but do not show the nucleophilic addition reaction like aldehydes or ketones. Why?
In the following reaction
\[\ce{Carbonyl compound + MeOH <=>[HCl] acetal}\]
Rate of the reaction is the highest for ______.
The product of following reaction is
\[\ce{CH3 - CH = CH - CH2 - CHO ->[i) LiAlH4][ii) H3O+]}\] ______?
Write the structure of the product formed when acetone reacts with 2, 4 DNP reagent.
Draw structure of the following derivative.
The ethylene ketal of hexan-3-one
Draw the structure of the following derivative.
The ethylene ketal of hexan-3-one
Draw structures of the following derivatives.
Acetaldehydedimethylacetal
Draw structure of the following derivative.
The ethylene ketal of hexan-3-one
Give an example of the reaction in the following case.
Oxime
