Question

iron reacts with lemon juice to form

Answer 1

the irons are reacting with the acids (citric.) to form soluble and insoluble iron oxides (hydroxides), iron  citrates and other acid (citric acid) pairs with the iron  and there are likely reactions with the limonenes, terpenes and other constituents in the juice.

remember that citric acid are in lemon juice :):):):):):):)