Which of the following compounds is an optically active compound?

Which of the following is a chiral compound?

$(+)$ $2-$Methylbutan$-1-$ol and $(-)$ $2-$Methylbutan$-1-$ol have different values for which property?

Which among the following compounds has a chiral carbon atom?

The concentration of an organic compound in chloroform is $6.15 \ g$ per $100 \ mL$ of solution. $A$ portion of this solution in a $5 \ cm$ polarimeter tube causes an observed rotation of $-1.2^{\circ}$. What is the specific rotation of the compound?

Which of the following compounds exhibits optical isomerism?