Final answer:
The cyclohexane boat conformation has one plane of symmetry due to the unfavorable steric interactions between the hydrogen atoms positioned at the bow and stern of the molecule.
Step-by-step explanation:
The subject of this question is Chemistry and it relates to the concept of molecular conformations, specifically focusing on cyclohexane. The student asks "How many planes of symmetry does a cyclohexane boat have?" Whereas the chair conformation of cyclohexane is more stable and has several planes of symmetry, the boat conformation is less stable and has only one plane of symmetry. This is because in the boat conformation, pairs of hydrogen atoms at the bow and stern of the molecule are close to each other, causing steric hindrance and thus, fewer planes of symmetry.
Additionally, cyclohexane is not a planar molecule. It is puckered to attain a bond angle of approximately 109.5°, with every other carbon atom above and below the plane of the molecule. This puckering allows the molecule to reduce ring strain. The boat conformation has a higher energy compared to the chair conformation and as a result, it is less common. The higher energy can be attributed to unfavorable steric interactions between hydrogen atoms.