Chemical Reaction Diagram (Mechanism for Carboxylation of Grignard): Here’s a reaction summary: Formation of Grignard Reagent (Twice) C₆H₄Br₂ + 2 Mg → C₆H₄(MgBr)₂ (in THF) Reaction with CO₂ (Dry Ice): C₆H₄(MgBr)₂ + 2 CO₂ (s) → C₆H₄(CO₂MgBr)₂ Acid Workup: C₆H₄(CO₂MgBr)₂ + 2 HCl → C₆H₄(CO₂H)₂ + 2 MgBrCl See more