Question

Let’s try another question.
Which of the following are possible wedge – dash representations for Glyceraldehyde.

Assume the H and OH on the second carbon are coming out of the plane.

• A.
• B.
• C.
• D.

Answer 1

Answer: (A), (D)

Let’s look at option A



Here we see that on the top carbon, 2 are above the plane, one is on the plane and one is below. This scenario is perfectly fine. So this is a possible representation.


Here if you see, on the top carbon there are 3 groups which are above the plane. If you think about it, this is not possible for a tetrahedral structure. You cannot have 3 groups above the plane all at once.



In this case, it has been shown like the bond between C and C is below the plane which is actually funny since that bond is always taken for the plane of reference. And even if you try to take some other plane, this scenario is just not possible.



This again is a perfectly possible scenario. Try and think about this for a while.