Question

why does calcium metal not deposit instead of sodium at the cathode?​

Answer 1

Answer:

The cell does not produce calcium metal because the electrowinning of sodium occurs at a less negative cathode potential than does the electrowinning of calcium.

Explanation:

The cell is designed to collect sodium at the cathode and chlorine at the anode without allowing these two products to react with each other. The melting point of sodium chloride is about 800oC, so a mixture whose mole ratio is about one mole of NaCl to three moles of CaCl2 is employed to reduce the melting point to about 600oC. (In the absence of NaCl, electrolysis of CaCl2 would indeed produce calcium metal at the cathode, and calcium metal is produced in just this way.)

Answer 2

The cell doesn't create calcium metal because the electrowinning of sodium happens at a more positive cathode potential than does the electrowinning of calcium.

Why is it so?

• The cell is intended to gather sodium at the cathode and chlorine at the anode without permitting these two items to respond to one another.
• The liquefying point of sodium chloride is around $800$°, so a combination whose mole proportion is around one mole  $NaCl$ to three moles  $CaCl_{2}$ is utilized to decrease the dissolving point to around $600$°.
• Without any $NaCl$, electrolysis  $CaCl_{2}$ would for sure deliver calcium metal at the cathode, and calcium metal is created only along these lines.

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