Distinction between pairs of compounds
Propan-1-ol `(CH_(3)CH_(2)CH_(2)OH)` and Propan-2-ol `(CH_(3)CHOHCH_(3))`

Explanation

Iodoform test helps to distinguish these. Propan-2-ol contains the grouping - `CHOHCH_(3)`. So, when it is warmed with `I_(2)//NaOH`, iodoform (yellow ppt.) is formed. Propan-1-ol does not contain this grouping. So, it does not give this test.
`underset("Propan-2-ol")(CH_(3)-CHOHCH_(3))+NaOIrarrunderset("Acetone")(CH_(3)-COCH_(3))+NaI+H_(2)O`
`CH_(3)COCH_(3)+3NaOIrarrundersetunderset(("yellow ppt."))("Iodoform")(CHI_(3))+underset("Sod. acetate")(CH_(3)COONa)+2NaOH`