The molecular mass of a hydrocarbon is $86 \ g/mol$. What is the number of its possible structural isomers?

What is the correct order of ease of replacement of the hydrogen atom by a chlorine atom in the following compound by photochlorination?

$A$ compound reacts with $Cl_2$ to give product $(B)$,and the reaction of product $(B)$ with $(Zn + \text{dilute } HCl)$ gives back the original substance $(A)$. Give the structures of $(A)$ and $(B)$.

$2, 3-$dimethylhexane contains tertiary,secondary,and primary carbon atoms,respectively:

Explain the dry-cleaning of clothes or explain why grease stains can be removed by petrol.

An alkane $(Y)$ requires $8$ moles of oxygen for complete combustion and on chlorination with $Cl_2/h\nu$, $(Y)$ gives only one monochlorinated product $(Z)$. The total number of primary carbon atoms in $(Y)$ is . . . . . . .