The compounds which contain either CH3−CO− groupor CH3—
C
|
OH
H group give positive iodoform test in 2-pentanone, (CH3CH2CH2COCH3) , CH3CHO‌and‌C2‌H5‌O‌H , these groups are present, thus they give iodoform as follows CH3−COCH2−CH2CH3+3I2+4NaOH→
CHI3↓
Iodoform(yellow‌ppt)
+CH3CH2CH2COONa+3NaI+3H2O CH3CHO+3I2+4NaOH→
CHI3↓
Iodoform(yellow‌ppt)
+HCOONa+3NaI+3H2O C2H5OH
I2
––––––––🢖
CH3CHO CH3CHO3I2+4NaOH→
CHI3↓
Iodoform
+HCOONa+3NaI+3H2O but du to bsence of CH3−
C
|
OH
H group in 3- pentanone, it does not give iodoform. CH3−CH2−
O
||
C
−CH2−CH3+I2+NaOH→ ‌‌‌‌‌‌‌‌‌‌‌‌‌3−pentan‌one No reaction