Question

The donor atom in EDTA are

• A. Two N and two O
• B. Two N and four O
• C. Four N and two O
• D. Three N and three O
• E. Two N and three O

Hint:

EDTA coordinates with metal ions in a 1:1 ratio using its six donor points to wrap around the metal.

Answer 1

The Correct Option is B

Concept: EDTA is a polydentate ligand. Its coordination ability comes from specific Nitrogen and Oxygen atoms within its chemical structure.

Step 1: {Identify the Nitrogen donor sites.}
The "ethylenediamine" part of the molecule contains two Nitrogen atoms, each possessing a lone pair available for coordination.

Step 2: {Identify the Oxygen donor sites.}
The "tetraacetic acid" part contains four carboxylate groups ($–COO^-$) after deprotonation. Each group provides one Oxygen atom for bonding.

Step 3: {Total the number of donor atoms.}
Summing the sites:
• Nitrogen donors = 2
• Oxygen donors = 4 Total denticity = 6 (Hexadentate).