The standard reduction potentials at (298 ~K ) for the following half cells are given below : ( array ll Cr ₂ O ₇²⁻+14 H ⁺+6 e ⁻ 2 Cr ³⁺+7 H ₂ O , E ^ =1.33 ~V Fe ³⁺( aq )+3 e ⁻ Fe E ^ =-0.04 ~V Ni ²⁺( aq )+2 e ⁻ Ni E ^ =-0.25 ~V Ag ⁺( aq )+ e ⁻ Ag E ^ =0.80 ~V Au ³⁺( aq )+3 e ⁻ Au E ^ =1.40 ~V array ) Consider the given electrochemical reactions, The number of metal(s) which will be oxidized be ( Cr ₂ O ₇²⁻ ), in aq