A hydroxy compound ( X ) with molar mass 122 g mol^-1 is acetylated with acetic anhydride, using a large excess of the reagent ensuring complete…

A hydroxy compound $\displaystyle (\mathrm{X})$ with molar mass $\displaystyle 122 \mathrm{~g} \mathrm{~mol}^{-1}$ is acetylated with acetic anhydride, using a large excess of the reagent ensuring complete acetylation of all hydroxyl groups. The product obtained has a molar mass of $\displaystyle 290 \mathrm{~g} \mathrm{~mol}^{-1}$. The number of hydroxyl groups present in compound $\displaystyle (\mathrm{X})$ is: