The stability of complexes of `Cu^(2+),Ni^(2+),Co^(2+)` and `Fe^(2+)` varies in the order

The order of stability of complex of ion CU^(+2),Ni^(+2),Mn^(+2) and Fe^(+2) decreases in the order-

In what order the reagents Na_(2)S, NaCl and Nal are added to an aqueous solution containing Ag^(+), Cu^(+2) and Ni^(+2) ions in order to precipitate Ag^(+) first Cu^(+2) second and Ni^(+2) last.

In what order the reagents Na_(2)S, NaCl and Nal are added to an aqueous solution containing Ag^(+), Cu^(+2) and Ni^(+2) ions in order to precipitate Ag^(+) first Cu^(+2) second and Ni^(+2) last.

Statement-1: The correct order for the wave length of absorption in the visible region is : [Ni(NO_(2))_(6)]^(4-)lt[Ni(NH_(3))_(6)]^(2+)lt[Ni(H_(2)O)_(6)]^(2+) Statement-2: The stability of different complexes depends on the strength of the ligands field of the various ligands.

The correct order of the number of unpaired electrons in the ions Cu^(2+), Ni^(2+), Fe^(3+) , and Cr^(3+) is