E⁰ values for Cl₂, Cl^- ; I₂, I^- , Ag⁺ , Ag; Na⁺ , Na; and Li⁺_, Li are respectively + 1.36, + 0.53, +0.79, -2.71 and - 3.04V. Correct decreasing order of reducing strength of Cl^-, I^-, Ag, Na and Li is

The given electrode potentials are reduction potentials of Cl₂ , I₂ , Ag⁺,Na⁺ & Li⁺
Reduction potentials value 

easy of reduction themselves
Oxidation potential values 

easy of oxidation themselves
Reduction potential values increases means reduction themselves increases that mean their oxidising power increases, hence their reducing power decrease
Hint
Oxidation potential values 

reducing power
Reduction potentials value 

oxidising power
Reducing strength
Li > Na > I^- > Ag > Cl^-