Sodium can be extracted by the electrolysis of sodium fluoride, which is obtained from mineral fluorite deposits.
The sodium fluoride is melted and then electrolysed. The positive electrode is made of graphite and the negative electrode is made of iron.
Sodium forms at the negative electrode. Fluorine forms at the positive electrode.
Explain why the sodium fluoride has to be melted before it can be electrolysed.
Write an ionic half-equation to represent the formation of sodium at the negative electrode.
Suggest why iron is not used for the positive electrode.
