Which one of the following is most stable?

Consider the sets $I$,$II$,and $III$. Identify the set$(s)$ which is (are) correctly matched.
$I$. $\text{Staggered ethane} > \text{eclipsed ethane} \dots \dots \dots \text{torsional strain}$.
$II$. $2, 2-\text{Dimethylbutane} > 2-\text{methylpentane} \dots \dots \dots \text{boiling point}$.
$III$. $cis-\text{but}-2-\text{ene} > trans-\text{but}-2-\text{ene} \dots \dots \dots \text{dipole moment}$.

Examine the following three pairs of possible isomers. Now state whether the pairs represent identical compounds or different isomers.

The compound $C_{4}H_{10}O$ can show which of the following types of isomerism?

Total number of stereo-isomers possible for the following compound is:
$1,2$-disubstituted cyclohexane with a $-\text{CH}_2\text{OH}$ group at position $1$ and a $-\text{CH}=\text{CH}-\text{CH}=\text{CH}-\text{CH}_2\text{CH}_3$ group at position $2$.

The process of separation of a racemic mixture into $d$ and $l$ enantiomers is called .............