check the box under each compound that exists as a pair of mirror - image twins. if none of them do, check…

check the box under each compound that exists as a pair of mirror - image twins. if none of them do, check the none of the above box under the table.\nnone of the above
Answer
Explanation:
Step1: Identify chiral centers
A chiral center is a carbon atom bonded to four different groups. In the first compound, the central carbon is bonded to -NH₂, -CH₃, -OH and -COOH, so it has a chiral center. In the second compound, the central carbon is bonded to -NH₂, -CH₃, -CH₃ and -COOH, so it does not have a chiral center (two -CH₃ groups are the same). In the third compound, the carbon is bonded to -NH₂, -H, -H and -COOH, so it does not have a chiral center (two -H groups are the same). In the fourth compound, the central carbon is bonded to -NH₂, -OH, -CH₂COOH and -COOH, so it has a chiral center. Compounds with chiral centers can exist as mirror - image twins (enantiomers).
Step2: Check for enantiomers
The first and fourth compounds can exist as mirror - image twins.
Answer:
Check the box under the first and fourth compounds.