The oxidation number of Pt in the complex [Pt(C₂H₄)Cl₃]^- is___________

Answer: + 2

Given complex [Pt(C₂H₄)Cl₃]^–

Let us consider the oxidation state of Pt be X

Since the complex’s total charge is 1, the sum of all elements’ oxidation states should also be 1.

X + 0 + 3(-1) = -1

X – 3 = -1

X = -1 + 3

X = +2