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Following compounds are given
a. $CH_3CH_2OH$
b. $CH_3COCH_3$
c. $CH_3CH(OH)CH_3$
d. $CH_3OH$
Which of the above compound(s), on being warmed with iodine solution and NaOH, will give iodoform?
a. $CH_3CH_2OH$
b. $CH_3COCH_3$
c. $CH_3CH(OH)CH_3$
d. $CH_3OH$
Which of the above compound(s), on being warmed with iodine solution and NaOH, will give iodoform?
A
a, c and d
B
Only b
C
a, b and c
D
a and b
Detailed Solution
The iodoform test (yellow precipitate of $CHI_3$ with $I_2$/NaOH) is given by compounds containing the $CH_3CO-$ group, and by alcohols containing the $CH_3CH(OH)-$ group, which are oxidised to $CH_3CO-$ by NaOI.
a. $CH_3CH_2OH$ has $CH_3CH(OH)-$ (with H); it is oxidised to $CH_3CHO$ and gives iodoform.
b. $CH_3COCH_3$ has the $CH_3CO-$ group; it gives iodoform.
c. $CH_3CH(OH)CH_3$ has the $CH_3CH(OH)-$ group; it is oxidised to acetone and gives iodoform.
d. $CH_3OH$ has neither group; it does not give iodoform.
Hence a, b and c give iodoform.
a. $CH_3CH_2OH$ has $CH_3CH(OH)-$ (with H); it is oxidised to $CH_3CHO$ and gives iodoform.
b. $CH_3COCH_3$ has the $CH_3CO-$ group; it gives iodoform.
c. $CH_3CH(OH)CH_3$ has the $CH_3CH(OH)-$ group; it is oxidised to acetone and gives iodoform.
d. $CH_3OH$ has neither group; it does not give iodoform.
Hence a, b and c give iodoform.