Match the entries of column I with appropriate entries of column II and choose the correct option out of the four options given. Column I (Compound) Column II (Oxidation state of Co) (a) [Co(NCS)(NH3)5](SO3) (i) +4 (b) [Co(NH3)4Cl2]SO4 (ii) 0 (c) Na4[Co(S2O3)3] (iii) +2 (d) [Co2(CO)8] (iv) +3

(a)-(ii), (b)-(i), (c)-(iii), (d)-(iv) (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii) (a)-(i), (b)-(iv), (c)-(iii), (d)-(ii) (a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)

(a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)

(a) [Co(NCS)(NH3)5](SO3) = x - 1 + 0 = +2 ⇒ x = 3 (b) [Co(NH3)4Cl2]SO4 = x + 0 - 2 = +2 ⇒ x = 4 (c) Na4[Co(S2O3)3] = x - 6 = -4 ⇒ x = +2 (d) [Co2(CO)8] = 2x + 0 = 0 ⇒ x = 0