The following reactions occur spontaneously as written.
2Cr2+(aq) + Co2+(aq) → 2Cr3+(aq) + Co(s)
Co(s) + Pb2+(aq) → Co2+(aq) + Pb(s)
Fe(s) + 2Cr3+(aq) → Fe2+(aq) + 2Cr2+(aq)
Using this information, predict which one of the following pairs of reactants will react spontaneously.
A. Co(s) + Fe2+(aq)
B. Cr2+(aq) + Fe2+(aq)
C. Cr2+(aq) + Pb2+(aq)
D. Pb(s) + Co2+(aq)
Solution
Which one of the following, under standard conditions, can not be predicted from the electrochemical series?
A. Fe2+(aq) is a stronger reductant than Br–(aq).
B. Fe2+(aq) is a stronger oxidant than Zn2+(aq).
C. Sn2+(aq) reacts faster with Ag+(aq) than with Cu2+(aq).
D. The equilibrium constant for the reaction between Sn2+(aq) and Cu2+(aq) is greater than the equilibrium constant for the reaction between Sn2+(aq) and Zn2+(aq).
Solution