What are $X$ and $Y$ respectively in the following sets of reactions?
$I. \ CH_3CH_2CH_2OH \xrightarrow{PBr_3} X$
$II. \ CH_3CH=CH_2 \xrightarrow{HBr, (C_6H_5COO)_2} Y \text{ (major)}$

In the following reactions,the product $S$ is

What is the decreasing order of acidic strength for ethane $(I)$,ethene $(II)$,ethyne $(III)$,and propyne $(IV)$?

In the given sequence of reactions,identify $P, Q, R$ and $S$ respectively.
$CH_2=CH_2 + Br_2$ $\xrightarrow{P} CH_2(Br)-CH_2(Br)$ $\xrightarrow{Q} CH_2=CH-Br$ $\xrightarrow{R} CH \equiv CH$ $\xrightarrow{S} C_6H_6$

Given below are two statements for the following reaction sequence.
Statement $I$: Compound $'Z'$ will give yellow precipitate with $NaOI$.
Statement $II$: Compound $'Q'$ has two different types of $'H'$ atoms (aromatic : aliphatic) in the ratio $1 : 3$.
In the light of the above statements,choose the correct answer from the option given below:

Identify the product $(C)$ in the following series of reaction:
$\text{Cyclopentane}$ $\xrightarrow{Br_2, hv} A$ $\xrightarrow{\text{alc. KOH}} B$ $\xrightarrow{\text{NBS}} C$