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प्रश्न
How are the following compounds prepared?
benzaldehyde from benzene
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उत्तर
(a) Benzaldehyde from benzene
Benzene
Gatterman Koch synthesis
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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
Draw the structure of the semicarbazone of ethanal.
Write the structures of the main products when acetone (CH3 − CO − CH3) reacts with the following reagent :
H2N − NHCONH2/H+
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.
Predict the product of the following reaction:
What is meant by the following term? Give an example of the reaction in the following case.
Cyanohydrin
What is meant by the following term? Give an example of the reaction in the following case.
Semicarbazone
What is meant by the following term? Give an example of the reaction in the following case.
Imine
Give plausible explanation for the following:
There are two −NH2 groups in semicarbazide. However, only one is involved in the formation of semicarbazones.
How are the following compounds prepared?
acetophenone from benzene
How will you convert sodium acetate to methane?
Acetone, Acetaldehyde, Benzaldehyde, Acetophenone – reactivity towards addition of HCN.
Write a test to differentiate between pentan-2-one and pentan-3-one.
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?
Arrange the following in the increasing order of their property indicated:
Ethanal, Propanone, Propanal, Butanone (reactivity towards nucleophilic addition)
The product "P" in the above reaction is:
Which of the following is most reactive in nucleophilic addition reactions?
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) |  |
Write the structure of the product formed when acetone reacts with 2, 4 DNP reagent.
Draw structures of the given derivatives.
The ethylene ketal of hexan-3-one
Draw structure of the following derivative.
The ethylene ketal of hexane-3-one
Draw structure of the following derivative.
Acetaldehydedimethylacetal
Draw structures of the following derivatives.
Acetaldehydedimethylacetal
Draw the structure of the following derivative.
Acetaldehydedimethylacetal
Draw structures of the given derivatives.
The ethylene ketal of hexan-3-one
Draw structure of the following derivative.
The ethylene ketal of hexan-3-one
Draw the structure of the given derivative.
The ethylene ketal of hexan-3-one
Give an example of the reaction in the following case.
Imine
