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प्रश्न
What is meant by the following term? Give an example of the reaction in the following case.
Oxime
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उत्तर
Oximes are formed by reaction between aldehydes or ketones and hydroxylamine. The reaction is carried out in a mildly acidic condition.
\[\begin{array}{cc}
\ce{H3C}\phantom{...........................}\ce{H3C}\phantom{.....................}\\
\backslash\phantom{..............................}\backslash\phantom{................}\\
\ce{= O + \underset{Hydroxylarnine}{H2N-OH} ->[pH 3.5] \phantom{......}= NOH + H2O}\\
/\phantom{..............................}/\phantom{.................}\\
\ce{H}\phantom{............................}\ce{\underset{Oxime}{H}}\phantom{..................}
\end{array}\]
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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
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.
Predict the product of the following reaction:
Predict the products formed when cyclohexanecarbaldehyde reacts with the following reagents.
Semicarbazide and weak acid
Complete the synthesis by giving missing starting material, reagent or product.
\[\ce{C6H5CHO ->[H2NCONHNH2]}\]
What is the action of the following reagents on ethanoic acid?
1) `LiAlH_4"/"H_3O^+`
2) `PCl_3 , "heat"`
3) `P_2O_5, "heat"`
Write a test to differentiate between pentan-2-one and pentan-3-one.
The pH of blood does not appreciably change by a small addition of acid or base because
Which one of the following gives only one monochloro derivative?
Grignard reagent on reaction with acetone forms.
Which among the following is most reactive to give nucleophilic addition?
Write the name of product formed, when acetone is treated with 2, 4-dinitrophenyl hydrazine.
What happens when propanone is treated with CH3MgBr and then hydrolysed?
What happens when ethanal is treated with excess ethanol and acid?
The product of following reaction is
\[\ce{CH3 - CH = CH - CH2 - CHO ->[i) LiAlH4][ii) H3O+]}\] ______?
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) |  |
Out of p-tolualdehyde and p-nitrobenzaldehyde, which one is more reactive towards nucleophilic addition reactions, why?
Draw structures of the given derivatives.
The ethylene ketal of hexan-3-one
Draw the structure of the following derivative.
Acetaldehydedimethylacetal
