$$ \text { From the following, how many compounds contain at least one secondary alcohol?} $$

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A hydroxy compound $(\mathrm{X})$ with molar mass $122 \mathrm{~g} \mathrm{~mol}^{-1}$ 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 $290 \mathrm{~g} \mathrm{~mol}^{-1}$. The number of hydroxyl groups present in compound $(\mathrm{X})$ is:

A mixed ether $(\mathrm{P})$, when heated with excess of hot concentrated hydrogen iodide produces two different alkyl iodides which when treated with aq. NaOH give compounds $(\mathrm{Q})$ and $(\mathrm{R})$. Both $(\mathrm{Q})$ and $(\mathrm{R})$ give yellow precipitate with NaOI . Identify the mixed ether $(\mathrm{P})$ :

$$ \text { 3, 3-Dimethyl-2-butanol cannot be prepared by : } $$

$$ \text { Choose the correct answer from the options given below : } $$