Sodium cannot be extracted by electrolysis of aqueous solutions due to

When aqueous NaCl solution is electrolysed, Cl_2​ is formed at the anode and Na at the cathode. But Na is very reactive with H_2​O forming NaOH and H₂​. Thus, Na cannot be prepared by electrolysis of aq. NaCl.
NaCl(aq) ⇌ Na⁺+Cl−
At anode: 2Cl−→Cl_2​+2e−
At cathode: 2Na⁺+2e⁻→2Na

2Na+2H₂​O→2NaOH+H_2​