Which of the following is the most suitable method for removing the traces of water from ethanol?

Alcohols react with active metals,e.g.,$Na, K$ etc. to give corresponding alkoxides. Write down the decreasing order of reactivity of sodium metal with primary,secondary and tertiary alcohols.

The products obtained in the following reaction are:

Identify the major product of the following reaction:
$(CH_3)_3C-CH(OH)-CH_3 \xrightarrow[\Delta]{\text{conc. } H_2SO_4} \text{Major product}$

Identify the alcohol that reacts immediately with Lucas reagent.

Identify $A, B, C,$ and $D$ in the following reaction sequence:
$CH_3-CH_2-CH(OH)-CH_3$ $\xrightarrow{PBr_3} (A)$ $\xrightarrow{Mg, \text{ether}} (B)$ $\xrightarrow{CH_3CHO} (C)$ $\xrightarrow{H_3O^+} (D)$