Chemical cells and fuel cells GapFill

When two connected metals with different reactivities are placed in an electrolyte,  a reaction profilean electrolysis set-upa simple cella catalyst is made. If these are placed in series,  a strong acidan alkalian electrolytea battery is formed, which provides a higher  voltagepHratetemperature than a single cell.

One type of battery is  a one-wayan alkalinea two-wayan acidic battery, which produces a voltage until the chemicals are  neutralisedgasessolidifiedused up. However, some cells can be  compresseddividedthrown away safelyrecharged because they contain chemicals which can undergo a reversible reaction when an external  pressureelectrical currentmagnetic fieldsource of hydrogen is supplied.

Fuel cells use a fuel such as hydrogen. They also take in  carbon dioxideoxygennitrogencarbon monoxide from the air. In these cells, hydrogen is  reducedcooledliquefiedoxidised to form  an alkaliwatermethanean alkane as the only product. This reaction produces  activation energygreenhouse gasesa change in pressurea potential difference. The half-equations for an electrochemical cell are:

• Cathode: H₂ (g) →  4H⁺4OH⁻2H⁺2OH⁻ (aq) + 2e⁻
• Anode: 4H⁺ (aq) + O₂ (g) +  2OH⁻ (aq)2e⁻6e⁻4e⁻ → 2H₂O (l)