A voltaic cell prepared using aluminum and nickel has the following cell notation. Which of the following represents the correctly balanced spontaneous reaction equation for the cell?

Question

A voltaic cell prepared using aluminum and nickel has the following cell notation.  Which of the following represents the correctly balanced spontaneous reaction equation for the cell?

Quizplus · Accepted Answer

The electrode on the left side of the cell notation (Al) is undergoing oxidation and losing electrons, becoming Al$^{3+}$ ions in solution. The electrode on the right side of the cell notation (Ni) is gaining electrons and being reduced, forming Ni$^{2+}$ ions in solution. Therefore, the overall spontaneous reaction must be:

2Al(s) + 3Ni$^{2+}$(aq) $\rightarrow$ 2Al$^{3+}$(aq) + 3Ni(s)

To balance the equation, we need to add electrons to the left side (since Al is losing electrons) and remove electrons from the right side (since Ni is gaining electrons). The balanced equation is:

3Ni$^{2+}$(aq) + 2Al(s) + 6e$^{-}$ $\rightarrow$ 3Ni(s) + 2Al$^{3+}$(aq)

This matches the balanced equation in choice B.

A Voltaic Cell Prepared Using Aluminum and Nickel Has the Following