How Many Chiral Carbons are Present in the Open-Chain Form

Question

How many chiral carbons are present in the open-chain form of an aldopentose?
A) two
B) three
C) four
D) five

Accepted Answer

An aldopentose has five carbon atoms in its open-chain form. Each of these carbons can potentially have four different substituents, making them chiral centers. Therefore, the open-chain form of an aldopentose contains five chiral carbons. Choice B, three, is not correct because it is not a possibility. Therefore, the only best choice is B.