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Explain Haloform reaction. |
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Answer» Solution : A ketone containing `-COCH_(3)`group is oxidised by sodium hypohalite and results in the formation of sodium salt of carboxylic acid having one carbon atom less than that of ketone and METHYL group is converted to HALOFORM. `CH_(3) - overset(O)overset(||)(C) - CH_(3)+3NaOl underset(Delta) overset(NaOH//X_(2))to R- overset(O)overset(||)C-overset(-)Ooverset(+)N + underset("haloform")(CHX_(3)) + 2NAOH` Acetaldehyde is the only aldehyde which gives haloform reaction. In this reaction, R may be hydrogen, methyl group or aryl group and X may be Cl , Br or I. When a methyl ketone is warmed with iodine and sodium hydroxide, a YELLOW precipitate of iodoform is obtained. The iodoform reaction is used as a qualitative test for detection of CH,CO-group in an organic compound . `CH_(3) - overset(O)overset(||)(C) - CH_(3)+ 3NaOl underset(Delta) overset(NaOH//I_(2))to CH_(3)-overset(O)overset(||)(C) - overset(-)Ooverset(+)Na+ underset("(Yellow percipitate)")underset("iodoform")(CHI_(3))+2NaOH` |
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