Examine the following half-reactions and select the strongest oxidizing agent among the species listed.

cr 2+(aq) + 2e- = cr (s) e= -0.913 v
fe 2+(aq) + 2e- = fe (s) e= -0.447 v
sr 2+(aq) + 2e- = sr (s) e= -2.89 v
co 2+(aq) + 2e- = co (s) e= -0.28 v

a. co 2+(aq)
b. fe (s)
c. fe 2+ (aq)
d. sr 2+ (aq)
e. cr 2+ (aq)

a. Co²⁺(aq)

Explanation:

The standard potential in a redox reaction (E) allows  the classification of different substances according to their oxidizing and reducing power.

For the reactions:

Cr²⁺(aq) + 2e⁻ = Cr(s) E= -0.913 V

Fe²⁺(aq) + 2e⁻ = Fe(s) E= -0.447 V

Sr²⁺(aq) + 2e⁻ = Sr(s) E= -2.89 V

Co²⁺(aq) + 2e⁻ = Co(s) E= -0.28 V

If the standard potential for the reaction is positive, the reaction will occur spontaneously. As these reactions are of reductions, the more positive E will be the strongest oxidizing agent. For that reason the right answer is:

a. Co²⁺(aq)

I hope it helps!

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.