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I'm an IGCSE Chemistry-extended student, and my question is: in electrolysis, does it make any difference if the electrolyte is in a molten, aqueous or dilute aqueous solution form? An example mentioned in my book:

Explain the difference in the electrolysis products of

a) molten sodium chloride;
b) dilute aqueous solution of sodium chloride.

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1 Answer 1

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In molten sodium chloride, the only available ions are $\ce{Na^+}$ and $\ce{Cl^-}$. With electrolysis, the products will be sodium metal and chlorine gas.

In an aqueous solution, the sodium chloride still moves the charges from one electrode to the other, but the potential for electrolysis of water is less than $\ce{Na^+}$ or $\ce{Cl^-}$. So the products of a solution of sodium chloride is hydrogen gas and oxygen gas.

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  • $\begingroup$ I think adding corresponding reactions would be a nice addition (for clarity). $\endgroup$
    – andselisk
    May 31, 2019 at 7:38
  • $\begingroup$ Depending on concentration, it may be chlorine instead of oxygen due oxygen overpotential $\endgroup$
    – Poutnik
    Jun 1, 2019 at 10:32

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