An organic compound of formula `C_(3)H_(8) O_(3)` yields on acetylation with acetic anhydride a derivative of the formula `C_()H_(14)O_(6)`. How many hydroxyl groups are present in the compound ?

Explanation

`R-OH overset((CH_(3)CO)_(2)O)(rarr)ROCOCH_(3)`
In this reaction for every -OH group, `C_(2)H_(2)O` is increased o acetylation.
Total increase `=C_(9)H_(14)O_(6)-C_(3)H_(8)O_(3)=C_(6)H_(6)O_(3)`
Thus, the increase is equivalent to the presence of 3-OH groups in the alcohol.