Question
The oxidation states of Cr in [Cr(H2O)6]Cl3,[Cr(C6H6)2], and K2[Cr(CN)2 (O)2(O2)(NH3)] respectively are :
+3, +2, and +4
+3, 0, and +6
+3, 0, and +4
+3, +4, and +6
Solution
B.
+3, 0, and +6
(i) [Cr(H2O)6]Cl3:Hexaaquachromium(III) chloride
x + 6 × 0 + (–1) × 3 = 0
x = +3
(ii) [Cr(C6H6)2] : bis(h6–benzene)chromium(0)
y + 2 × 0 = 0
y =0 =
(iii) K2[Cr(CN)2 (O)2 (O2) (NH3)] :
Potassium amminedicyanidodioxidoperoxidochromate(VI)
2 × 1 + z + 2 × (–1) + 2 × (–2) + (–2) + 0 = 0
z = +6
The oxidation states of Cr in [Cr(H2O)6]Cl3, [Cr(C6H6)2], and K2 [Cr(CN)2 (O)2 (O2) (NH3)]
respectively are +3, 0 and +6.
