Explain the iodoform test.
(N/A) Aim: The iodoform test is used to identify compounds containing the $CH_3CO-$ group (methyl ketones) or compounds that can be oxidized to this group,such as $CH_3CH(OH)-$ (secondary alcohols) and ethanol.
Procedure: The compound is treated with iodine $(I_2)$ in the presence of sodium hydroxide $(NaOH)$. This generates sodium hypoiodite $(NaOI)$ in situ.
Reaction: $R-CO-CH_3 + 3I_2 + 4NaOH \rightarrow R-COONa + CHI_3 + 3NaI + 3H_2O$
Observation: The formation of a yellow precipitate of iodoform $(CHI_3)$ indicates a positive test result.
Note: Ethanol $(CH_3CH_2OH)$ also gives this test because it is oxidized to acetaldehyde $(CH_3CHO)$ by sodium hypoiodite,which then undergoes the iodoform reaction.
Procedure: The compound is treated with iodine $(I_2)$ in the presence of sodium hydroxide $(NaOH)$. This generates sodium hypoiodite $(NaOI)$ in situ.
Reaction: $R-CO-CH_3 + 3I_2 + 4NaOH \rightarrow R-COONa + CHI_3 + 3NaI + 3H_2O$
Observation: The formation of a yellow precipitate of iodoform $(CHI_3)$ indicates a positive test result.
Note: Ethanol $(CH_3CH_2OH)$ also gives this test because it is oxidized to acetaldehyde $(CH_3CHO)$ by sodium hypoiodite,which then undergoes the iodoform reaction.
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Similar Questions
Which one among the following reaction products gives the iodoform test?
DifficultTS EAMCET 2020
View SolutionMatch the compounds/ions in Column $I$ with their properties/reactions in Column $II$.
Column $I$ Column $II$ $A$. $C_6H_5CHO$ $p$. gives precipitate with $2, 4-$dinitrophenylhydrazine $B$. $CH_3C \equiv CH$ $q$. gives precipitate with $AgNO_3$ $C$. $CN^{-}$ $r$. is a nucleophile $D$. $I^{-}$ $s$. is involved in cyanohydrin formation
| Column $I$ | Column $II$ |
|---|---|
| $A$. $C_6H_5CHO$ | $p$. gives precipitate with $2, 4-$dinitrophenylhydrazine |
| $B$. $CH_3C \equiv CH$ | $q$. gives precipitate with $AgNO_3$ |
| $C$. $CN^{-}$ | $r$. is a nucleophile |
| $D$. $I^{-}$ | $s$. is involved in cyanohydrin formation |
DifficultIIT 2007
View SolutionFehling's solution is a mixture of two solutions. One of them is $CuSO_4$. What does the other solution contain?
Medium
View SolutionThe product in the given reaction is:
Which of the following compounds will not react with phenylhydrazine?
Medium
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