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प्रश्न
When liquid ‘A’ is treated with a freshly prepared ammoniacal silver nitrate solution, it gives bright silver mirror. The liquid forms a white crystalline solid on treatment with sodium hydrogensulphite. Liquid ‘B’ also forms a white crystalline solid with sodium hydrogensulphite but it does not give test with ammoniacal silver nitrate. Which of the two liquids is aldehyde? Write the chemical equations of these reactions also.
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उत्तर
Liquid ‘A’ forms a bright silver mirror on treatment with ammoniacal \[\ce{AgNO3}\] solution, therefore, liquid ‘A’ is an aldehyde.
Liquid B does not give test with ammoniacal \[\ce{AgNO3}\] solution, therefore, liquid ‘B’ must be a methyl ketone.
Chemical equations for these reactions are:
\[\begin{array}{cc}
\phantom{........}\ce{R}\phantom{......................}\ce{R}\phantom{.......}\ce{SO3Na}\phantom{}\\
\phantom{...}\backslash\phantom{......................}\backslash\phantom{...}\phantom{..}/\\\
\phantom{}\ce{C = O + NaHSO3 -> \phantom{..}C}\\
\phantom{.............}/\phantom{......................}/\phantom{.....}\backslash\phantom{..........}\\
\phantom{.....}\ce{\underset{Aldehyde(A)}{H}\phantom{................}\underset{(White crystalline solid)}{\phantom{.}H\phantom{.......}OH}}\phantom{..}
\end{array}\]
\[\begin{array}{cc}
\phantom{........}\ce{R}\phantom{......................}\ce{R}\phantom{.......}\ce{SO3Na}\phantom{}\\
\phantom{...}\backslash\phantom{......................}\backslash\phantom{...}\phantom{..}/\\\
\phantom{}\ce{C = O + NaHSO3 -> \phantom{..}C}\\
\phantom{.............}/\phantom{......................}/\phantom{.....}\backslash\phantom{..........}\\
\phantom{....}\ce{\underset{Methyl ketone (B)}{H3C}\phantom{.............}\underset{(White NaHSO3 adduct)}{\phantom{.}H3C\phantom{.......}OH}}\phantom{.....}
\end{array}\]
\[\ce{\underset{Aldehyde (A)}{R - CHO} + \underset{Tollens reagent}{2[Ag(NH3)2]+} OH- ->[Warm] RCOONH4 + \underset{(Silver mirror)}{2Ag + 3}NH3 + H2O}\]
\[\begin{array}{cc}
\ce{O}\phantom{...............................}\\
||\phantom{...............................}\\
\ce{\underset{Methyl ketone (B)}{R - C - CH3} ->[Tollens reagent] No silver mirror}
\end{array}\]
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संबंधित प्रश्न
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Butane-1, 3-diol
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\[\begin{array}{cc}
\ce{C6H5CHO}\phantom{............}\\
\phantom{........}\ce{+\phantom{......}\ce{->[dil.NaOH][\Delta]}}\phantom{...}\\
\ce{CH3CH2CHO}\phantom{............}
\end{array}\]
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Why are carboxylic acids more acidic than alcohols or phenols although all of them have hydrogen atom attached to a oxygen atom \[\ce{(-O-H)}\]?
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Cross aldol condensation occurs between
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
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Ethanal to 3-hydroxy butanal
\[\ce{CH3-CH2-CHO ->[dil][alkali] Product}\]
The product in the above reaction is:
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Which of the following does not give aldol condensation reaction?
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Reason (R): α, β-unsaturated carbonyl compounds are stabilised due to conjugation.
Identify A and B:
When acetaldehyde is treated with dilute NaOH, the following reaction is observed.
\[\begin{array}{cc}
\ce{2CH3 - CHO ->[dil.NaOH] CH3 - CH - CH2 - CHO}\\
\phantom{...............}|\\
\phantom{.................}\ce{OH}
\end{array}\]
- What are the functional groups in the product?
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- Is this an addition reaction or condensation reaction?
Write a note on the aldol condensation reaction of acetaldehyde.
