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प्रश्न
Describe the following:
Cross aldol condensation
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उत्तर
When aldol condensation is carried out between two different aldehydes and/or ketones, it is called cross aldol condensation. If both of them contain a-hydrogen atoms, it gives a mixture of four products. This is illustrated below by the aldol reaction of a mixture of ethanal and propanal.
Ketones can also be used as one component in the cross-aldol reactions.
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संबंधित प्रश्न
What is meant by the following term? Give an example of the reaction in the following case.
Aldol
How will you convert ethanal into the following compound?
But-2-enal
Write structural formulas and names of four possible aldol condensation products from propanal and butanal. In each case, indicate which aldehyde acts as nucleophile and which as electrophile.
Complete the synthesis by giving missing starting material, reagent or product.
\[\begin{array}{cc}
\ce{C6H5CHO}\phantom{............}\\
\phantom{........}\ce{+\phantom{......}\ce{->[dil.NaOH][\Delta]}}\phantom{...}\\
\ce{CH3CH2CHO}\phantom{............}
\end{array}\]
Give reasons Acetylation of aniline reduces its activation effect.
Write chemical equations of the following reaction :
Propanone is treated with dilute Ba (OH)2-.
Write a chemical equation for the following reaction:
Propanone is treated with dilute Ba( OH)2.
Explain aldol condensation reaction in detail.
Which of the following compounds do not undergo aldol condensation?
(i) \[\ce{CH3 - CHO}\]
(ii) 
(iii) \[\begin{array}{cc}
\phantom{}\ce{O}\\
\phantom{}||\\
\ce{CH3 - C - CH3}
\end{array}\]
(iv) \[\begin{array}{cc}
\phantom{}\ce{CH3}\\
|\phantom{...}\\
\ce{CH3 - C - CHO}\phantom{..}\\
|\phantom{...}\\
\phantom{}\ce{CH3}\\
\end{array}\]
Why is there a large difference in the boiling points of butanal and butan-1-ol?
Give reasons to support the answer:
Presence of Alpha hydrogen in aldehydes and ketones is essential for aldol condensation.
Identify A and B from the following reaction:
\[\begin{array}{cc}
\ce{CH3}\phantom{.................}\\
|\phantom{....................}\\
\phantom{}\ce{2CH3 - C = O ->[Ba(OH)2] A ->[Δ] B + H2O}
\end{array}\]
Convert the following:
Acetaldehyde to But-2-enal
Which of the following compounds will undergo self-condensation in the presence of dilute NaOH solution?
Write a note on the aldol condensation reaction of acetaldehyde.
Which one of the following undergoes reaction with 50% sodiumhydroxide solution to give the corresponding alcohol and acid:
