in the reaction:Ni+SN4+-->Ni2+ (+)Sn2+ which species has been reduced?

Question

1.Ni
2.Sn4+
3.Ni2+
4.Sn2+

i know its def Sn but im not sure which one.

Answer 1

Remember Leo the Lion goes Grr. The key word is Leo; i.e., loss electrons oxidation. So reduction is the gain of electrons. If you know it's Sn, then does Sn gain electrons in going from Sn+4 to Sn+2 or from Sn+2 to Sn+4.