Question

A student was trying to obtain lithium by electrolysis of aqueous lithium chloride. Was he successful?

Answer 1

The student was not successful.

Consider the standard reduction potentials.

Li⁺ + e⁻ ⇌ Li;                       E° = -3.04 V

2H₂O + 2e⁻ ⇌ H₂ + 2OH⁻; E° = -0.83 V

To reduce Li⁺ to Li, the student must apply 3.04 V.

However, it takes only 0.83 V to reduce water to hydrogen.

Thus, the student will get H₂ instead of Li.