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प्रश्न
Write the main product formed when propanal reacts with the following reagents:
H2N- NH2 followed by heating with KOH in ethylene glycol.
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उत्तर
\[\ce{CH3CH2CHO + H2N - NH2 -> CH3CH2CH = N - NH2 + H2O}\]
This is a nucleophilic addition-elimination process where the carbonyl group (C = O) is replaced with a hydrazone group \[\ce{(C = N - NH2)}\].
The hydrazone is then heated with KOH in ethylene glycol, a strong base under high-temperature conditions. This leads to the loss of nitrogen gas (N2) and the reduction of the carbon–nitrogen double bond to a C–H bond.
\[\ce{CH3CH2CH = N - NH2 \overset{KOH/ethylene glycol,Δ}{->} CH3CH2CH3 + N2 ↑}\]
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संबंधित प्रश्न
Predict the product of the following reaction:
How are the following compounds prepared?
acetophenone from benzene
Write balanced chemical equations for action of ammonia on - acetone
Arrange the following in the increasing order of their property indicated:
Ethanal, Propanone, Propanal, Butanone (reactivity towards nucleophilic addition)
The following questions are case-based questions. Read the passage carefully and answer the questions that follow:
| The carbon-oxygen double bond is polarised in aldehydes and ketones due to higher electronegativity of oxygen relative to carbon. Therefore, they undergo nucleophilic addition reactions with a number of nucleophiles such as HCN, NaHSO3, alcohols, ammonia derivatives and Grignard reagents. Aldehydes are easily oxidised by mild oxidising agents as compared to ketones. The carbonyl group of carboxylic acid does not give reactions of aldehydes and ketones. Carboxylic acids are considerably more acidic than alcohols and most of simple phenols. |
Answer the following:
(a) Write the name of the product when an aldehyde reacts with excess alcohol in the presence of dry HCl. (1)
(b) Why carboxylic acid is a stronger acid than phenol? (1)
(c) (i) Arrange the following compounds in increasing order of their reactivity towards CH3MgBr: (1)
CH3CHO, \[\begin{array}{cc}
\ce{(CH3)3C-C-CH3}\\
\phantom{....}||\\
\phantom{....}\ce{O}
\end{array}\], \[\begin{array}{cc}
\ce{CH3-C-CH3}\\
||\\
\ce{O}
\end{array}\]
(ii) Write a chemical test to distinguish between propanal and propanone. (1)
OR
(c) Write the main product in the following: (2)
| (i) |  |
| (ii) |  |
Draw the structure of the following derivative.
The ethylene ketal of hexane-3-one
Draw structure of the following derivative.
The ethylene ketal of hexane-3-one
Draw structure of the following derivative.
The ethylene ketal of hexan-3-one
Give an example of the reaction in the following case.
Oxime
Give an example of the reaction in the following case.
Imine
