Which of the following redox reactions do you expect to occur spontaneously in the reverse direction?
Check all that apply-
1) 2Ag+(aq) + Ni(s) ------> 2Ag(s) + Ni2+ (aq)
2) Fe(s) + Mn2+(aq) ------> Fe2+(aq) + Mn(s)
3) 2Al(s) + 3Pb2+(aq)-----> 2Al3+(aq) +3Pb(s)
4) Ca2+(aq) + Zn(s) -------> Ca(s) + Zn2+(aq)