The hydrocarbon with the common name fluorene is acidic enough (pK a 23) to be a

Question:

The hydrocarbon with the common name fluorene is acidic enough (pK_a ≈ 23) to be a useful indicator in deprotonation reactions of compounds of greater acidity. Indicate the most acidic hydrogen(s) in fl uorene. Draw resonance structures to explain the relative stability of its conjugate base.

Fluorene