The denticity of the ligand present in the Fehling's reagent is__________. — JEE Mains Chemistry Past Papers Chemistry Question

💡 Solution & Explanation

# Solution: Denticity of Fehling's Reagent Ligand **Step 1: Identify the ligand in Fehling's reagent** Fehling's reagent contains copper(II) complexed with tartrate ions. The primary ligand is tartrate (C₄H₄O₆²⁻), also known as the L-tartrate ion. **Step 2: Understand denticity definition** Denticity refers to the number of donor atoms in a ligand that coordinate to the central metal ion. **Step 3: Identify donor atoms in tartrate** The tartrate ligand has the structure with two carboxylate groups (-COO⁻). Each carboxylate group contains oxygen atoms capable of donating electron pairs to the metal center. **Step 4: Count coordination points** The tartrate ion coordinates through: - Oxygen atoms from the first carboxylate group (2 oxygens, but acts as one donor site) - Oxygen atoms from the second carboxylate group (2 oxygens, acts as one donor site) - The hydroxyl groups (-OH) also participate in coordination Tartrate coordinates as a **bidentate** ligand through its two carboxylate oxygen atoms. **Step 5: Confirm the structure** In Fehling's reagent, tartrate acts as a chelating agent, binding to Cu²⁺ through two coordinate bonds. Therefore, the answer is **2 (bidentate)**.