Question

What are some examples of electrochemical processes?

Answer 1

Galvanic cells are a great example of an electrochemical process.

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The galvanic cell has the capability of deriving electrical energy from spontaneous REDOX reactions that take place within the cell. The cell consists of two different metals connected together by a salt bridge.

Electrons will always flow from the oxidation half cell (the anode) to the reduction half cell (the cathode) - in other words, from the more negative half reaction to the more positive half reaction.

Another great example of an electrochemical process is corrosion. A piece of bare iron will rust quickly when exposed to moisture, the corrosion rate being enhanced by an electrochemical process in which a water droplet becomes a miniature galvanic cell in contact with the metal (it oxidizes the iron).

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Iron supplies electrons at the edge of the droplet to reduce oxygen from the air - the iron surface inside the droplet acts as the anode for the process

`Fe_((s)) -> Fe_((s))^(2+) + 2e^-`

The electrons move through the iron to the outside of the water droplet, where

`O_(2(g)) + 2H_2O(l) + 4e^(-) -> 4OH(aq)^-`

The hydroxide ions now react with the iron ions to form iron (III) hydroxide (a precipitate)

`Fe_((aq))^(2+) + 2OH^(-)(aq) -> Fe(OH)_2(s)`

Rust is then produced by the oxidation of the precipitate

`4Fe(OH)_2(s) + O_2(g) -> 2Fe_2O_3 * H_2O_((s)) + 2H_2O_((l))`

Here's a video of electrochemical machines, another example of REDOX reactions applications

and a video on corrosion