how to manufacture sodium hydroxide?

we can manufacture sodium hydroxide by manufacture of chlorine bleach
first of all, collect brine (sea water/conc NaCl solution)
by electrolysis of brine with running mercury as the cathode
and graphite rod as anode
sodium amalgam will be formed at cathode
Na+ + e- + Hg → Na/Hg
then, add water to sodium amalgam
sodium hydroxide will be formed
2Na/Hg + 2H2O → 2NaOH + H2 + 2Hg
collect the sodium hydroxide formed

1:放sodium落水
2Na+2H2O>2NaOH+H2
(好少會咁製造)

2:用鹽水電解,會做出氫,氯,氫氧化鈉