Arrange these species by their ability to act as an oxidizin

Arrange these species by their ability to act as an oxidizing agent. Au3+, Sn+2,Cr+2,Ca+2

Solution

Ca^2+ (aq) + 2e^- --------------> Ca(s)       E0   = -2.76v

Cr^2+ (aq) + 2e^- --------------> Cr(s)        E0   = -0.91v

Sn^2+ (aq) + 2e^- ----------------> Sn(s)      E0 = -0.14v

Au^3+ (aq) + 3e^- ------------>   Au(s)          E0 = 1.5v

The reduction potential value more ion is strong oxidizing agent.

The ability to increasing oxidizing agent.

Au^3+ > Sn^2+ > Cr^2+ >ca^2+