Which of the following is the correct decreasing order of water solubility for the given organic compounds?

The decreasing order of dehydration of the following alcohols is:

$C_{4}H_{10}O$ $\xrightarrow{K_{2}Cr_{2}O_{7} / H_{2}SO_{4}} C_{4}H_{8}O$ $\xrightarrow{I_{2} / NaOH, \text{Warm}} CHI_{3}$
Here, $N$ is

In the Victor-Meyer's test,the colours given by $1^o$,$2^o$,and $3^o$ alcohols are respectively:

$CH_3 CH_2 OH \underset{\text{step-}1}{\stackrel{Cl_2}{\longrightarrow}} CH_3 CHO$ $\underset{\text{step-}2}{\stackrel{3 Cl_2}{\longrightarrow}} Cl_3 CCHO$
In the above reactions,the role of $Cl_2$ in step-$1$ and step-$2$ respectively is:

$PCl_5$ reacts with a compound containing