Electrolysis of concentrated and dilute NaCl

Question 1

List ions formed

both for concentrated and dilute solutions

Answer 1

H+ and OH‾ from water

Cl‾ and Na+ from NaCl

Question 2

Conc. NaCl

reactions that take place at different electrodes

Answer 2

anode: chlorine gas released
2Cl → Cl₂ + 2e¯
cathode: hydrogen gas is released
2H → H₂ +2e¯

Question 3

Dil. NaCl

reactions that take place at different electrodes

Answer 3

anode: oxygen is produced
4OH¯ → O₂ + H₂O + 4e¯
cathode: hydrogen gas released
2H → H₂ +2e¯