Fuel Cells 🔋⚡

Fuel cells let us grab the chemical energy of a fuel and flip it straight into electric energy—no noisy turbines or smoky chimneys needed. Because they skip the “boil-water-run-turbine” route, they hit about 70 % efficiency, while a typical power plant sits near 40 %. :contentReference[oaicite:0]{index=0}

Hydrogen–Oxygen Fuel Cell 🚀

  • We bubble H2 and O2 through porous carbon electrodes dunked in concentrated NaOH(aq).
  • Finely divided Pt or Pd on the electrodes speeds up each reaction.
  • The cell keeps going as long as you feed the gases and remove the water made.
  • Apollo spacecraft used this cell; the condensed water became drinking water for astronauts. 🌌🚰

Electrode Reactions 🧪

Cathode (oxygen):
\( \text{O}_2(g) + 2\text{H}_2\text{O}(l) + 4e^- \; \rightarrow \; 4\text{OH}^-(aq) \) :contentReference[oaicite:1]{index=1}

Anode (hydrogen):
\( 2\text{H}_2(g) + 4\text{OH}^-(aq) \; \rightarrow \; 4\text{H}_2\text{O}(l) + 4e^- \) :contentReference[oaicite:2]{index=2}

Overall:
\( 2\text{H}_2(g) + \text{O}_2(g) \; \rightarrow \; 2\text{H}_2\text{O}(l) \) 🔥➡️💧 :contentReference[oaicite:3]{index=3}

Why Fuel Cells Rock 🌍

  • High efficiency: ~70 % beats most engines and power plants.
  • Clean exhaust: only water comes out, so zero air pollution.
  • Continuous power: just keep the gases flowing and the cell hums along.
  • Wide use: engineers have already tested fuel-cell cars and buses. 🚗⚡

Quick Tips for NEET ✨

  1. Remember the cathode and anode half-reactions (they love asking those!).
  2. Overall cell reaction is simply H2 + O2 → H2O.
  3. Note the alkaline electrolyte (concentrated NaOH) and Pt/Pd catalysts.
  4. Fuel cells boast about 70 % efficiency versus ~40 % for thermal plants.
  5. Water produced doubles up as drinking water in space missions—cool trivia! 🚀