Given following reduction potentials in solution. Which is weakest oxidising agent in the list. List of numbers on right is for Eo/V.

Question

Al3+(aq)+3e- = Al(s) -1.66
Sn4+(aq)+2e- = Sn2+(aq) +0.14
Is(s)+2e-=21-(aq) +0.53

Why is a certain substance weakest? Is it -1.66 because this is negative compared to the other positive values.

Answer 1

As a reduction (as written). the three potentials represent oxidizing ability. The weakest is Al^+3 because of the -1.66
v
Written as oxidation, Al is the strongest reducing agent because it is +1.66 v.