Acidic dehydration of alcohol involves

Write the reactions for the conversion of methanol into ethanol,propan-$2$-ol,and $2$-methylpropan-$2$-ol.

The final product $A$,formed in the following reaction sequence is:
$Ph-CH=CH_2$ $\xrightarrow[\text{(iii) } HBr, \text{ (iv) } Mg, \text{ ether, then } HCHO / H_3O^{+}]{\text{(i) } BH_3, \text{ (ii) } H_2O_2, OH^{-}} A$

$C_6H_6$ $\xrightarrow[(ii)\,\,Zn-Hg/HCl]{(i)\,\,CH_3COCl/AlCl_3}$ $(P)$ $\xrightarrow[(ii)\,\,H_2O/K_2CO_3]{(i)\,\,NBS}$ $(Q)$
Major product $(Q)$ of the following sequence is:

$X$ and $Y$ respectively are

In which of the following reactions is a $2^o$ alcohol obtained as a product?