Which of the following compounds gives a yellow precipitate with $I_2$ and $NaOH$?

An organic compound $(A)$ reacts with sodium metal to form $(B)$. When $(A)$ is heated with concentrated $H_2SO_4$,it forms diethyl ether. What are $(A)$ and $(B)$ respectively?

Which among the following is a Lucas reagent?

Lucas test is used for the determination of

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

Oxidation of ethanol by chromic acid forms