Question

When current is passed through molten sodium chloride
A. Sodium is deposited at the positive electrodes and chlorine gas is formed at the negative
B. Sodium is evaporated and chloride ions are formed at the negative electrode
C. Sodium is deposited at the positive electrode and chlorine is deposited at the negative electrode
D. Sodium is deposited at the negative electrode and the chlorine gas is formed at the positive electrode

Answer 1

Hint: When electricity is passed through molten salt or any solution of salts, ions start moving around. This causes flow of current through the molten sodium chloride. When current is passed, the molten NaCl gets splitted into its elements. This causes the formation of ${Na}^{+}$ and ${Cl}^{-}$ ions. Positive and negative ions move in opposite directions to each other. So, these basics can be used to find what happens when current is passed through a molten sodium chloride.

Complete step by step answer:
When current is passed through molten NaCl i.e. sodium chloride, it decomposes into sodium and chlorine gas. Both sodium and chlorine gas move towards the electrode opposite to their own charge and either loses an electron or gains one. Sodium ${Na}^{+}$ is a positive ion so it moves towards the negative electrode while chlorine ${Cl}^{-}$ is a negative ion so it moves towards the positive electrode. Hence, the sodium ion deposits at the negative electrode while the chlorine gas is formed at the positive electrode.

So, the correct answer is option D i.e. sodium is deposited at the negative electrode and the chlorine gas is formed at the positive electrode.

Note:
Students should remember that this happens only when current is passed through molten sodium chloride. Whereas, if we make current pass through a molten sodium then nothing would happen as sodium is a metal. Students must also remember that when current is passed through the molten sodium chloride, there are no free electrons moving around, the current is due to the free ions.