The oxidation number of Co in given complex is x+4×0+1(−1)+1(−1)=+1 x=+3 The IUPAC name of the given complex [Co(NH3)4Cl(NO2)]Cl is tetraamminechloridonitrito-N-cobalt(III) chloride. NO2− is an ambidentate ligand name is nitrito-N means linkage is from N atom