Number of cycloalkanes having the molecular formula $C_5H_{10}$?

Photochemical chlorination of an alkane is initiated by a process of

$C_3H_8 + Cl_2 \xrightarrow{\text{Light}} C_3H_7Cl + HCl$ is an example of which of the following types of reactions?

How many primary,secondary,tertiary,and quaternary carbons are present in the following hydrocarbon?
$CH_3-CH(CH_3)-C(CH_3)_2-CH_2-CH(CH_3)-CH_2-CH_3$
Select the correct count for (Primary,Secondary,Tertiary,Quaternary) carbons respectively:

Given below are two statements $:$
Statement $(I) :$ Neopentane forms only one monosubstituted derivative.
Statement $(II) :$ Melting point of neopentane is higher than $n-$pentane.
In the light of the above statements,choose the most appropriate answer from the options given below $:$

$A$ hydrocarbon $C_5H_{12}$ does not react with chlorine in the dark but gives six monochloro compounds in bright sunlight. The hydrocarbon is: