CHEMISTRY HELP!?!?! URGENT!!?

a.
__ 2Ag(s) → 2Ag⁺(aq) + 2e⁻ …… E° = -0.80 V
+) Mg²⁺(aq) + 2e⁻ → Mg(s) …… E° = -2.37 V
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2Ag(s) + Mg²⁺(aq) → 2Ag⁺(aq) + Mg(s) …… E°(cell) = (-0.80) + (-2.37) = -3.17 V
As E°(cell) is negative, the reaction is non-spontaneous.


b.
__ 2Al(s) → 2Al³⁺(aq) + 6e⁻ …… E° = +1.66 V
+) 3Zn²⁺(aq) + 6e⁻ → 3Zn(s) …… E° = -0.76 V
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2Al(s) + 3Zn²⁺(aq) → 2Al³⁺(aq) + 3Zn(s) …… E°(cell) = (+1.66) + (-0.76) = +0.90 V
As E°(cell) is positive, the reaction is spontaneous.