Complex X of composition Cr(H₂O)₆Cl_n has a spin only magnetic moment of 3.83 BM. It reacts with AgNO₃ and shows geometrical isomerism. The IUPAC nomenclature of X is :

The de Broglie wavelength of an electron in the 4th Bohr orbit is :

The major product (Y) in the following reactions is :

The electronic configurations of bivalent europium and trivalent cerium are
(atomic number : Xe = 54, Ce = 58, Eu = 63)