Consider the Fischer projection formula for (S)-2-chlorobutaneWhich of the following changes does not convert this structure to the (R)-enantiomer?

Flipping the structure over (a 180º rotation out of the plane)

Rotation 180º in the plane of the paper (or screen)

Exchanging the two vertical substituents (i.e. top and bottom)

Exchanging the two horizontal substituents (i.e. right and left)

Consider the Fischer projection formula for (S)-2-chlorobutaneWhich of

1.	Consider the Fischer projection formula for (S)-2-chlorobutaneWhich of the following changes does not convert this structure to the (R)-enantiomer?
A.	Rotation 180º in the plane of the paper (or screen)
B.	Flipping the structure over (a 180º rotation out of the plane)
C.	Exchanging the two vertical substituents (i.e. top and bottom)
D.	Exchanging the two horizontal substituents (i.e. right and left)
Answer» B. Flipping the structure over (a 180º rotation out of the plane)