Question

Using the relative E0 values determine which of the following reactions are electrically possible. Mg(s) + Br2(I) ⟶ MgBr2

Choose the answer from the parenthesis.
This equation shows that Mg is (reduced or oxidized)

This equation shows that Br2 is (reduced or oxidized)

Can this redox reaction take place? (yes or no)

Answer 1

The correct answers are Mg is oxidized, Br2 is reduced, and yes this redox reaction can take place.

Answer 2

To determine if the reaction provided is electrically possible, we can first separate the overall reaction into its half-reactions:

Mg (s) + Br₂ (l) → MgBr₂

Mg → Mg²⁺ + 2e⁻ E = -2.37 V

Br₂ + 2e⁻ → 2Br⁻ E = 1.09 V

Looking at the half-reactions, we can see that magnesium loses electrons in the process which means that magnesium is oxidized.

Since bromine is gaining electrons, Br₂ is being reduced.

Now to determine if this reaction is taking place, we must find the reduction potentials for each half-reaction. To final the overall potential of the cell, we take the difference in the cathode (reduction) and anode (oxidation) potentials.

Ecell = Ecathode - Eanode

Ecell = 1.09 V - (-2.37 V)

Ecell = 3.46 V

A positive value of Ecell means that the reaction will happen spontaneously. Therefore, this reaction is electrically possible and will take place.