Primary alcohols on dehydration give

Which of the following compounds has the highest boiling point?

In the following reaction sequence,the compound $I$ is:
$I (C_3H_6Cl_2)$ $\xrightarrow{KOH_{(aq)}} II$ $\xrightarrow{(i) CH_3MgBr, (ii) H_2O/H^{+}} III$ $\xrightarrow{Anhy. ZnCl_2 + Conc. HCl}$ gives turbidity immediately.

Ethyl alcohol will give ethyl chloride with the help of which of the following?

Most acidic alcohol out of the following compounds is

$CH \equiv CH$ $\xrightarrow{\text{Red hot Fe tube}} A$ $\xrightarrow{CH_3COCl / AlCl_3} B$ $\xrightarrow{(1) LiAlH_4 / (2) H_3O^\oplus} C$
$C$ will be