Redox PDF
Redox PDF
Redox PDF
Voltaic cells
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Standard hydrogen
electrode (SHE)
• A H+ / H2 half cell with an equilibrium established between H+ and H2 at standard conditions (298
K, 1.00 atm and 1.00 moldm–3)
• 2 H+ (aq) + 2 e– ⇌ H2 (g) – E = 0.00 V (arbitrarily assigned)
• Electrode potential varies with changes in temperature, partial pressure of gases and
concentration
of ions
Salt bridges
• A salt bridge is included to complete the electrical circuit by allowing the movement of ions
without introducing any more particles into the system
• It is also used to maintain electrical neutrality in the cell
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Notation
- Oxidation is written first and slashes represent phase boundaries
- Reduction is written second
- The double slash in the notation represents the salt bridge
- If more than one species in the same phase is present, a comma is used to separate them
- If there is no conducting solid species, platinum is used as the inert electrode
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