In Na extraction from $\ce{NaCl}$, $\ce{CaCl2}$ is added in electrolysis to lower the melting point of the mixture to about $\pu{750 ^\circ C}$. But doesn't $\ce{Ca^2+}$ cation compete with the $\ce{Na+}$ ion to be reduced at the cathode? If so, since $\ce{Ca^2+}$ is right next to the electrochemical series, should we not have a considerable amount of $\ce{Ca}$ as impurity in the $\ce{Na}$ that we have extracted? Where do the inconsistencies lie?

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    $\begingroup$ Electrochemical series is for aqueous solution only! $\endgroup$
    – Mithoron
    Aug 13 '20 at 22:27
  • $\begingroup$ @Mithoron, Got it, thanks. But in this case, how will one decide which cation will be reduced without the help of the electrochemical series? $\endgroup$
    – Habib
    Aug 13 '20 at 22:50
  • $\begingroup$ Well, there are data for various solvents and melts, not nearly as commonly found or thorough, though. $\endgroup$
    – Mithoron
    Aug 13 '20 at 22:54

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