Be sure to answer all parts. write equations for the oxidation of fe and of al. use δg o f to determine whether either process is spontaneous at 25°c. (a) equation for oxidation of iron: δg o rxn : kj is the oxidation of iron spontaneous at 25°c? yes no (b) equation for the oxidation of aluminum: δg o rxn : kj is the oxidation of aluminum spontaneous at 25°c? yes no

(a) Fe(s) ⇒ Fe²⁺(aq) + 2 e⁻

ΔG° = -85 kJ

Spontaneous

(b) Al(s) ⇒ Al³⁺(aq) + 3 e⁻

ΔG° = -480 kJ

Spontaneous

Explanation:

(a) The equation for the oxidation of iron is:

Fe(s) ⇒ Fe²⁺(aq) + 2 e⁻      E° = 0.44 V

We can calculate the standard Gibbs free energy (ΔG°) using the following expression.

ΔG° = -n. F. E°

where,

n are the moles of electrons transferred

F is the Faraday's constant

ΔG° = -2 mol × (96,468 × 10⁻³ kJ/V.mol) × 0.44 V = -85 kJ

ΔG° < 0, which means that the reaction is spontaneous.

(b) The equation for the oxidation of aluminum is:

Al(s) ⇒ Al³⁺(aq) + 3 e⁻      E° = 1.66 V

ΔG° = -3 mol × (96,468 × 10⁻³ kJ/V.mol) × 1.66 V = -480 kJ

ΔG° < 0, which means that the reaction is spontaneous.

it is b that is the answer.