How many EDTA (ethylenediaminetetraacetic acid) molecules are required to make an octahedral complex with a Ca2+ ion?
Answer & explanation
Correct answer: option 2
The correct answer is option 2. One.
EDTA (ethylenediaminetetraacetic acid) is a hexadentate ligand, meaning it can form up to six coordinate bonds with a single metal ion. In forming a complex, EDTA typically coordinates through its two amine nitrogen atoms and four carboxylate oxygen atoms.
A Ca\(^{2+}\) ion requires six coordination sites to form a stable octahedral complex. Since EDTA can provide all six coordination sites by itself, only one EDTA molecule is required to make an octahedral complex with a Ca\(^{2+}\) ion.
Therefore, the correct answer is: One.