X, B, C and Z are the elements belonging to 17^th group of Modern periodic table. The correct trend of reducing power of their ions is X^- > B^- > C^- > Z^-. The element ‘Z’ in the sequence is

detailed solution

Correct option is D

Atomic radius….FCl>Br>I;EN ….F>Cl>Br>I;Electron gain enthalpy ….ICl>Br>I>Cl->F->Br->I-B.D.E….Cl2>Br2>F2>I2; Due to small size and repulsions between lone pairs on adjacent Fluorine atoms ;IP …..I-Cl2>Br2>I2;Due to high hydration enthalpy of F- and low B.D.E of F2, F2 is the strongest oxidant and highly reactive;SRP Values of E12F2/F-0+2.87 V > E12Cl2/Cl-0+1.36 V > E12Br2/Br-0+1.08 V > E12I2/I-0+0.54 V ;Reducing power….I- > Br- > Cl- > F- ;Hydration enthalpy…F->Cl->Br->I-;MP and BP ….F2