In my exam, my teacher asked me if the following is true: "The chair cyclohexane has more axial hydrogens" I did not have time to think, so I just put false. And apparently I was right. But, at home, I thought to myself: Does this question even make sense? Axial hydrogens are by definition only seen on cyclohexanes according to what I know.
It says fully: TRUE OR FALSE: Boat cyclohexane is a slightly higher energy conformer than chair cyclohexane because: (a).... (a sub question) T OR F (b).... (a sub question) T OR F (c)chair cyclohexane has more axial hydrogens. T OR F
The answer to part (c) of that question is "False." It turns out that the chair and boat conformations of cyclohexane both have 6 axial hydrogens - so the chair does not have more axial hydrogens. Here's a picture of the chair (on the left) and boat (in the middle), you should be able to see the 6 axial hydrogens in both the chair and the boat.
If you want to be very precise (perhaps pedantic), then I would conclude that the question itself is a little dubious without additional clarification. Consider the IUPAC recommendation on Basic Terminology of Stereochemistry. It contains the following definition of axial with respect to ring conformations (emphasis mine):
In the chair form of cyclohexane ring bonds to ring atoms (and molecular entities attached to such bonds) are termed axial or equatorial according to whether the bonds make a relatively large or small angle, respectively, with the plane containing or passing closest to a majority of the ring atoms.
The point here is that the definition is contextually limited to chair conformations. Granted, this is only a recommendation, but I think it's a logical and authoritative one. Seen in that light, the question itself is malformed inasmuch as it admits either answer in the absence of an agreement on exact terms. To wit, "true" might be a valid answer, since by the strictest definition a boat conformation has zero axial hydrogens; on the other hand, if a similar definition (based on bond angles relative to a plane containing a majority of ring atoms) is applied to the boat conformation, one can identify six axial hydrogens roughly analogous to those in the chair conformation and the correct answer would be "false." Really, the question is murky unless you (and more importantly, your professor) are clear on the formal definition being used.
In my exam, my teacher asked me if the following is true: "The chair cyclohexane has more axial hydrogens" I did not have time to think, so I just put false. And apparently I was right.
What's the complete question? The chair form has more axial hydrogens than what other form? If the test were referring to the other chair conformation, then you are right.
Cyclohexane has 12 hydrogens, and in its two chair conformations, six substituents are axial while the other are equatorial.
Basically, the question is does boat have more axial H's than cyclohexane?
The boat conformation doesn't have any true axial positions. I'm not sure what your professor considers to be axial or not, but if we take the flagpole hydrogens to be "axial," then both the chair and the boat should still have the same number of axial substituents.
TRUE OR FALSE: Boat cyclohexane is a slightly higher energy conformer than chair cyclohexane because: (a).... (a sub question) T OR F (b).... (a sub question) T OR F (c)chair cyclohexane has more axial hydrogens. T OR F
Regarding the question now in context the instability of the boat conformation likely has more to do with flagpole-eclipsing interactions rather than the number of hydrogens.