Final answer:
Dilute solutions of NaCl are more conducive to hydrogen gas production because water is reduced, while concentrated solutions produce more chlorine gas since there are more chloride ions available for oxidation.
Step-by-step explanation:
The electrolysis of sodium chloride (NaCl) can yield different products depending on the concentration of the solution and the conditions of electrolysis. When you electrolyze dilute sodium chloride (NaCl) using inert electrodes, the preferred reduction at the cathode is the production of hydrogen due to water's lower reduction potential. Hence, dilute solutions produce more hydrogen gas. On the other hand, in concentrated sodium chloride solutions, there are more chloride ions available to be oxidized at the anode, leading to the production of more chlorine gas.
In summary, the key difference between the electrolysis of dilute and concentrated sodium chloride solutions lies in the quantity of the gases produced. Dilute solutions are more likely to produce hydrogen gas over sodium metal due to the reduction potential difference, while concentrated solutions produce more chlorine gas since there is a higher concentration of chloride ions available for oxidation.
The reaction at the cathode in diluted NaCl solution can be represented as:
2H2O(l) + 2e- → H2(g) + 2OH-(aq)
And the anode reaction in more concentrated NaCl solution is:
2Cl-(aq) → Cl2(g) + 2e-