The compounds which contain either CH3−CO− groupor CH3−OH∣CH group give positive iodoform test in 2-pentanone, (CH3CH2CH2COCH3) , CH3CHO and C2H5OH , these groups are present, thus they give iodoform as follows CH3−COCH2−CH2CH3+3I2+4NaOH→Iodoform (yellow ppt)CHI3↓+CH3CH2CH2COONa+3NaI+3H2OCH3CHO+3I2+4NaOH→Iodoform (yellow ppt)CHI3↓+HCOONa+3NaI+3H2OC2H5OHI2CH3CHOCH3CHO+3I2+4NaOH→IodoformCHI3↓+HCOONa+3NaI+3H2Obut du to bsence of CH3−OH∣CH group in 3- pentanone, it does not give iodoform.CH3−CH2−C∥O−CH2−CH3+I2+NaOH→3-pentanone3−pentanoneNo reaction