JEE Main Chemistry Class 12 Co-ordination Compounds Part 2 Questions

Secondary valency is equal to coordination number of central metal ion. In this reaction, central metal atom iron is attached with 3-oxalato ligand, and oxlaic acid it is a bidentate ligand i.e. have two donor sites. So, coordination number or secondary valency =3×2=6 Hence, product A have iron with secondary valency =6