(A) An inexpensive way to produce peroxodisulfates would be to pass O₂(g) through an acidic solution containing sulfate ion. Is this method feasible under standard conditions?

(B) Consider the following observations: 

(1) Aqueous solutions of Sn²⁺ are difficult to maintain because atmospheric oxygen easily oxidizes Sn²⁺ to Sn⁴⁺ 

(2) One way to preserve the Sn²⁺ solutions is to add some metallic tin. Without doing detailed calculations, explain these two statements by using E° data.