Standard reduction potentials of the half reactions are given below:
F2(g) + 2e⁻ → 2F⁻(aq); E⁰ = +2.85 V
Cl2(g) + 2e⁻ → 2Cl⁻(aq); E⁰ = +1.36 V
Br2(l) + 2e⁻ → 2Br⁻(aq); E⁰ = +1.06 V
I2(g) + 2e⁻ → 2I⁻(aq); E⁰ = +0.53 V
The strongest oxidizing and reducing agents respectively are:

The strongest oxidizing agent is the one with the highest standard reduction potential. In this case, F2(g) has the highest E⁰ value (+2.85 V), making it the strongest oxidizing agent. The strongest reducing agent is the one that is most easily oxidized, meaning it has the lowest standard reduction potential. This corresponds to I⁻, which is the conjugate base of I2(g) (E⁰ = +0.53V). Therefore, the strongest oxidizing and reducing agents are F2 and I⁻ respectively.