The highest possible oxidation state shown by osmium in its compound is_______.

(a)

+4

(b)

+6

(c)

+8

(d)

+10

The trend in ionisation enthalpy of a transition element is not regular because,_______.

(a)

removal of one electron alters the relative energies of 4s and 3d orbitals

(b)

due to different electronic configuration (stability)

(c)

Poor screening of 3p-orbital

(d)

due to decrease in effective nuclear charge

Which one of the following exhibits highest oxidation state?

(a)

Ni

(b)

Mn

(c)

V

(d)

Zr

Which of the following is coloured due to charge transfer?

(a)

MnO₄^-

(b)

CrO₄^2-

(c)

Cu₂O

(d)

All of these

What are the species X and Y in the following?

(a)

CrO₃, CrO₄^2-

(b)

CrO₃, Cr₂O₃

(c)

CrO₄^-2, Cr₂O₇^2-

(d)

H₂CrO₄, H₂Cr₂O₇