The optical rotation of a racemic mixture is always......

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 is not chiral?

The absolute configurations of the following compounds are respectively:

Explain the difference between asymmetric (chiral) and symmetric (achiral) molecules.

Meso-tartaric acid is optically inactive due to the presence of