Question

Determine the spontaneous redox reaction that occurs when the chemicals below are mixed, the standard cell potential, and the number of electrons transferred. Use the lowest possible coefficients and include states-of-matter. Use the link Standard Reduction Potentials. 1) Al3+/Al +Fe2+/Fe 2) Sodium Bromide is added to a solution containing flourine

Answer 1

2 Al(s) + 3 Fe²⁺(aq) → 2 Al³⁺(aq) + 3 Fe(s)

6 electrons are transferred.

Step-by-step explanation:

Let's consider the following standard reduction potentials.

E°(Al³⁺/Al) = -1.66 V

E°(Fe²⁺/Fe) = -0.44 V

The one with the highest standard reduction potential will occurs as a reduction and the other will occur as an oxidation. The corresponding half-reactions are:

Oxidation: Al(s) → Al³⁺(aq) + 3 e⁻

Reduction: Fe²⁺(aq) + 2 e⁻ → Fe(s)

To get the global equation, we have to multiply both half-reactions by numbers that assure that the number of electrons gained and lost are the same, and then add them.

2 × (Al(s) → Al³⁺(aq) + 3 e⁻)

3 × (Fe²⁺(aq) + 2 e⁻ → Fe(s))

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2 Al(s) + 3 Fe²⁺(aq) + 6 e⁻ → 2 Al³⁺(aq) + 6 e⁻ + 3 Fe(s)

2 Al(s) + 3 Fe²⁺(aq) → 2 Al³⁺(aq) + 3 Fe(s)