Identify the correct statements from the following:
$(i)$ Petrol and $CNG$ operated automobiles cause less pollution.
$(ii)$ Alkanes having tertiary hydrogen can be oxidised to alcohols by $KMnO_4$.
$(iii)$ Methane can be prepared by Kolbe's electrolytic method.
$(iv)$ Alkyl chloride on reduction with zinc and dilute hydrochloric acid gives alkane.

Given below are two statements:
Statement $I$ : The boiling point of three isomeric pentanes follows the order
$n$-pentane $>$ isopentane $>$ neopentane
Statement $II$ : When branching increases,the molecule attains a shape of sphere. This results in smaller surface area for contact,due to which the intermolecular forces between the spherical molecules are weak,thereby lowering the boiling point.
In the light of the above statements,choose the most appropriate answer from the options given below:

On exciting $Cl_2$ molecule by $UV$ light,we get

Consider the following:
Statement-$I$ : Kolbe's electrolysis of sodium propionate gives $n$-hexane as product.
Statement-$II$ : In Kolbe's process,$CO_2$ is liberated at the anode and $H_2$ is liberated at the cathode.
The correct answer is:

$RMgI$ when treated with ice-cold water liberated a gas which occupied $1.4 \text{ dm}^3/\text{g}$ at $STP$. The gas produced is further reacted with iodine in the presence of $HIO_3$ to give compound $(X)$. Compound $(X)$ in the presence of $Na$ and dry ether produced compound $(Y)$. The molar mass of compound $(Y)$ is . . . . . . $\text{g mol}^{-1}$. (Nearest integer)

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