Identify the product '$B$' in the following reaction sequence:
$CH_3CH_2CH(OH)CH_3 \xrightarrow{PBr_3} A \xrightarrow{Mg, \text{dry ether}} B$

Given below are two statements $:$
Statement $(I) :$ Alcohols are formed when alkyl chlorides are treated with aqueous potassium hydroxide by elimination reaction.
Statement $(II) :$ In alcoholic potassium hydroxide,alkyl chlorides form alkenes by abstracting the hydrogen from the $\beta-$carbon.
In the light of the above statements,choose the most appropriate answer from the options given below $:$

The mechanism of $S_{N}1$ reaction is given as:
$R-X$ $\rightarrow R^{\oplus} X^{\ominus}$ $\rightarrow R^{\oplus} | X^{\ominus}$ $\xrightarrow{Y^{\ominus}} R-Y + X^{\ominus}$
(Ion pair) (Solvent separated ion pair)
$A$ student writes general characteristics based on the given mechanism as:
$(a)$ The reaction is favoured by weak nucleophiles
$(b)$ $R^{\oplus}$ would be easily formed if the substituents are bulky
$(c)$ The reaction is accompanied by racemization
$(d)$ The reaction is favoured by non-polar solvents.
Which observations are correct?

Which among the following statements is $TRUE$ about gammexane?

Identify the correct order for the given property for the following compounds. Choose the correct answer from the options given below:
$(A)$ Boiling Point: $CH_3CH_2Cl < CH_3CH_2CH_2Cl < CH_3CH_2CH_2CH_2Cl$
$(B)$ Density: $CH_3CH_2Br < CH_3CH_2Cl < CH_3CH_2I$
$(C)$ Boiling Point: $CH_3CH_2Br < (CH_3)_2CHBr < (CH_3)_3CBr$
$(D)$ Density: $CH_3CH(I)Br < CH_3CH_2CH_2Br < CH_3CH(Br)Cl$
$(E)$ Boiling Point: $CH_3CH_2CH_2CH_2Cl > (CH_3)_2CHCH_2Cl > (CH_3)_3CCl$

The reaction of $n$-propyl bromide with alcoholic potassium hydroxide $(KOH)$ produces ...........