Which of the following redox reactions do you expect to occurspontaneously 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)