question_answer 82)

    Match the compounds given in Column I with the oxidation state of cobalt present in it (given in column II) and assign the correct code.

Column I (Compound)	Column II (Oxidation state of Co)
A.	1.    +4
B.	2.      0
C.	3.    +2
D.	4.    +3

  Code                                                   .       A  B   C    D                        A   B   C   D (a) 1   2   4   3                   (b) 4   3   2   1 (C) 3   1   4   2                   (d) 4   1   3   2

Answer:

                    A.- ®(4)    B.®(1)    C.®(3)    D.®(2) Oxidation state of CMI (central metal ion) can be calculated by considering the oxidation state of whole molecule is equal to charge present on coordination sphere. A.  Let oxidation state of Co is a.                             x - 1 + 5 ´ 0 = + 2                                   x = + 2 + 1 = + 3 B. Let oxidation state of Co = x                        x + 4 ´ 0 + 2 ´ (-1) = + 2 Þ                            x ? 2 = + 2 Þ                                   x = 4 C. Let oxidation state of Co = x                                  x + 3 x (-2) = - 4                                   x ? 6 = - A                                    x = - 4 + 6 = + 2 D. Let oxidation state of Co = x                                       x ? 8 x 0 = 0                                             x = 0                                     Hence, correct choice is (d).