A fuel cell differs from a battery because the current is being generated from a reduction-oxidation (redox) reaction in which the reactant is consumed. A classic example of a fuel cell is the phosphoric acid fuel cell (PAFC), which have been used in stationary power generators, buses, and even submarines. Fuel cells require an electrolyte (similar to batteries) to carry electrically charged species between the electrodes, and a PAFC utilizes phosphoric acid (H

3

PO

4

H3PO4) as its electrolyte.

 

The weak acid phosphoric acid has three acidic protons, highlighted in red here: H

3

PO

4

H3PO4. As a weak acid, some of the acid will remain in molecular form when dissolved in water. Write the net ionic equation that depicts the dissociation of the first proton including charges for any ions produced.

A fuel cell differs from a battery because the current is being generated from a reduction-oxidation (redox) reaction in which the reactant is consumed. A classic example of a fuel cell is the phosphoric acid fuel cell (PAFC), which have been used in stationary power generators, buses, and even submarines. Fuel cells require an electrolyte (similar to batteries) to carry electrically charged species between the electrodes, and a PAFC utilizes phosphoric acid (H3PO4 as its electrolyte.

The weak acid phosphoric acid has three acidic protons, highlighted in red here: H3PO4. As a weak acid, some of the acid will remain in molecular form when dissolved in water. Write the net ionic equation that depicts the dissociation of the first proton including charges for any ions produced.

H₃PO₄(aq) + H₂O(l) ? H₂PO₄^-(aq) + H₃O⁺(aq)

The first ionization of H₃PO₄ donating one of its protons to water. As a result, the charge of H₃PO₄ will decrease by one and its formula will include one less hydrogen atom (since a proton is what is lost). In contrast, H₂O accepts a proton so its formula will include one more hydrogen atom and its charge will increase by 1.