State that a hydrogen-oxygen fuel cell uses hydrogen and oxygen to produce electricity with water as the only chemical product

What is a Fuel Cell?

A fuel cell is like a never‑ending battery that keeps producing electricity as long as it has fuel (hydrogen) and oxygen. Think of it as a tiny power plant that runs on clean fuel – the only thing it spits out is water! 💧

How Does It Work?

The cell has two electrodes (anode and cathode) separated by an electrolyte. Hydrogen gas (H₂) is fed to the anode, while oxygen gas (O₂) is fed to the cathode. Electrons flow through an external circuit, giving you electricity, and then recombine with protons at the cathode to form water.

• 🔋 Anode reaction: \$\mathrm{H}_2 \rightarrow 2\mathrm{H}^+ + 2e^-\$
• 💧 Cathode reaction: \$\mathrm{O}2 + 4\mathrm{H}^+ + 4e^- \rightarrow 2\mathrm{H}2\mathrm{O}\$
• ⚡ Overall reaction: \$2\mathrm{H}2 + \mathrm{O}2 \rightarrow 2\mathrm{H}_2\mathrm{O}\$

Key Components

Exam Tip: Remember the Big Picture

When you write the overall reaction, highlight that the only chemical product is water. This is a key point that examiners look for. Also, be ready to explain why the cell produces electricity (electron flow) and why the electrolyte is essential (ion conduction). Good luck! 🍀