Redox reaction

Oxidation

Voltaic cell

Reduction

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Lose electron, Gain oxygen

Gain electron, Lose oxygen

Oxidation state

Oxidation state is a number which, together with its sign, indicates the gain or loss of electron control of an atom during a reaction.

Oxidation number is the numerical part of that value.

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Rust prevention

Fe (s) → Fe2+ (aq) + 2e−

Balance redox reaction

Electrolytic cell

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Anode

Cathode

Oxidation

Reduction

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Standard electrode potentials

Electrolysis of aqueous solutions

Standard hydrogen electrode(SHE)

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Note the following conditions of the SHE:

hydrogen gas, H2 (g), at a pressure of 100 kPa and temperature of 298 K

acidic solution with a [H+] of 1.0 mol dm–3

inert platinum electrode.

E⦵>0 Oxidation

E⦵<0 Reduction

E⦵cell = E⦵half-cell where reduction occurs − E⦵half-cell where oxidation occurs

ΔG⦵ = – nFE⦵

Compare standard electrode potentials to deduce the species that occur at Anode or Cathode

Electrolysis of water

Electroplating

Cathode is objected to be plated