Cobalt is present in which vitamin?
Ans. is 'd' i.e., Vitamin B12* Vitamin B1 or thiamine is structurally an aminopyrimidine ring linked by a methylene bridge with a thiazole ring* Hence thiamine is a sulphur containing vitamin* Vitamin B3 or niacin is structurally nicotinic acid and it is C6H5N02. It has nitrogen and not cobalt* Vitamin B5 or pantothenic acid is pantoic acid linked to p alanine. It's coenzyme form is CoA. Coenzyme A is p mercaptoethanolamine linked to pantothenic acid and 3'5'ADP. Hence it does not have cobalt.* Vitamin B12 has cobalt present in the centre of a planar tetrapyrrole ring. So four of the valencies of cobalt are satisfied by the four pyrrole rings. Fifth valency is satisfied by dimethylbenzimidazole group.
Vitamin B1
Vitamin B3
Vitamin B5
Vitamin B12
Vitamins and Minerals