A student carries out an electrolysis experiment using a concentrated aqueous solution of sodium chloride. Inert carbon electrodes are used. The student measures the volume of gas collected at the cathode over a measured time during which a constant current is passed.
(a) Describe the chemical reactions occurring at each electrode during the electrolysis of concentrated aqueous sodium chloride.
(b) State the relationship between the Faraday constant, , the Avogadro constant, , and the charge on the electron, . Describe how the student could use the experimental data (current, time, and volume of gas at the cathode) to determine a value for the Avogadro constant.
(c) The student repeats the experiment using a very dilute aqueous solution of sodium chloride. Predict how the products at each electrode differ from those in the concentrated solution, and explain your reasoning.