Answer:
See the explanation
Step-by-step explanation:
Our reactions for this question are:
a) Cr+3(aq) + 3e- → Cr(s) ________
b) Ag(s) → 1e- + Ag+1(ag) ________
c) Mn(s) → 5e- + Mn+5(aq) ________
d) Sn+2(aq) + 2e- → Sn(s) ________
Now, we have to remember the definition of oxidation and reduction. In a reduction reaction, the substance will gain electrons, in other words: "The electrons would be placed on the left side, in the side of the reagents. In an oxidation reaction, the substance will lose electrons, in other words: "The electrons would be placed on the right side, in the side of the products".
With this in mind we will have:
a) Cr+3(aq) + 3e- → Cr (s)(Reduction)
b) Ag(s) → 1e- + Ag+1(ag) (Oxidation)
c) Mn(s) → 5e- + Mn+5(aq) (Oxidation)
d) Sn+2(aq) + 2e- → Sn(s) (Reduction)
I hope it helps!