Q. The metal ion present in vitamin B12 is:

Explanation by: Mr. Dubey

Vitamin B12 (also known as Cobalamin) contains Cobalt (Co) as its central metal ion.
The presence of cobalt gives vitamin B12 its characteristic red color.
It is essential for red blood cell formation, DNA synthesis, and nervous system function.
Why are the other options incorrect?
Nickel (A) → Found in some enzymes but not in Vitamin B12.
Iron (C) → Essential for hemoglobin but not present in B12.
Zinc (D) → Important for immunity and enzyme function, but not in B12.
Thus, the correct answer is (B) Cobalt.