Final answer:
In E2 eliminations, the hydrogen atom that is being removed needs to be in the same plane as the leaving group, which is true. This coplanar arrangement is necessary for the elimination to take place efficiently.
Step-by-step explanation:
The statement that the H atom in an elimination in a ring must be in the same plane as the leaving group is true. This requirement is part of the chemical mechanism known as E2 elimination. In an E2 elimination, the hydrogen atom that is being removed must be coplanar with the leaving group in order for the elimination to occur, typically resulting in a double bond. This means that the H atom and the leaving group should ideally be aligned 180° from each other in the transition state, which is more stable when they are in the same plane. This allows the electrons from the C-H bond to overlap with the orbitals of the leaving group, facilitating the elimination process.