What is obtained when ethyl alcohol is heated with red phosphorus and $HI$?

Which among the following is an allylic secondary alcohol?

What are $X$ and $Y$ in the following reactions?

The compound $A$ on treatment with $Na$ gives $B$,and with $PCl_{5}$ gives $C$. $B$ and $C$ react together to give diethyl ether. $A, B$ and $C$ are in the order

An organic compound $(A)$ (molecular formula $C_{6}H_{12}O_{2}$) was hydrolysed with dil. $H_{2}SO_{4}$ to give a carboxylic acid $(B)$ and an alcohol $(C).$ $C$ gives white turbidity immediately when treated with anhydrous $ZnCl_{2}$ and conc. $HCl$. The organic compound $(A)$ is

Tertiary alcohols $(3^{\circ})$ having at least four carbon atoms upon drastic oxidation yield carboxylic acid with: