Which of the following hydrocarbons is exceptionally acidic (compared to standard alkanes or alkenes — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Cyclopentadiene ($C_5H_6$) readily loses a proton ($H^+$) from its $sp^3$ hybridized carbon to form the cyclopentadienyl anion ($C_5H_5^-$). This anion is planar, fully conjugated, and possesses $6\ \pi$ -electrons, making it aromatic and thus providing a massive thermodynamic driving force for the deprotonation.