which of the following are spontaneous reactions? 

Consider the following combination of reactants.

Sn(NO3)2(aq) and Cr(NO3)2(aq)

Co(s) and HCl(aq)

Fe(NO3)2(aq) and KMnO4(aq)

CuSO4(aq) and Cd(s)

ZnCl2(aq) and Pb(s)