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प्रश्न
What is meant by the following term? Give an example of the reaction in the following case.
Acetal
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उत्तर
Gem-dialkoxy compounds in which two alkoxy groups are present on the terminal carbon atom are called acetals. These are formed when the aldehyde reacts with two equivalents of monohydric alcohol in the presence of dry hydrogen chloride.
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संबंधित प्रश्न
Predict the products of the following reactions:
Write the products formed when CH3CHO reacts with the following reagents : H2N – OH
How will you bring about the following conversion in not more than two steps?
Bromobenzene to 1-Phenylethanol
Give plausible explanation for the following:
There are two −NH2 groups in semicarbazide. However, only one is involved in the formation of semicarbazones.
Complete the synthesis by giving missing starting material, reagent or product.
\[\ce{C6H5CHO ->[H2NCONHNH2]}\]
Write balanced chemical equations for action of ammonia on - acetone
How will you convert sodium acetate to methane?
Give a simple chemical test to distinguish between 
Write the main product formed when propanal reacts with the following reagents:
2 moles of 3 CH OH in presence of dry HCl
Write the main product formed when propanal reacts with the following reagents:
H2N- NH2 followed by heating with KOH in ethylene glycol.
Write a test to differentiate between pentan-2-one and pentan-3-one.
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.
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 structures of the given derivatives.
The ethylene ketal of hexan-3-one
Why dissociation of HCN is suppressed by the addition of HCL?
The product of the following reaction is
\[\begin{array}{cc}
\ce{O}\phantom{.........}\\
||\phantom{.........}\\
\ce{C2H5 - C - CH3 ->[H2/Ni][\Delta] \phantom{..}?}\end{array}\]
Draw the structure of the following derivative.
The ethylene ketal of hexan-3-one
Draw structure of the following derivative:
Acetaldehydedimethylacetal
