Question

Electrolytic cells use electricity to cause a nonspontaneous redox reaction to occur. An electrolytic cell is constructed using the following components: a power source, such as a battery, the substance that will undergo electrolysis, and two inert electrodes (usually platinum), which serve as the electrical connection between the power source and the substance undergoing electrolysis. As with any cell, oxidation occurs at the anode and reduction occurs at the cathode. The oxidation of water, which produces oxygen (O2) gas, will compete with the oxidation of the anion, and the reduction of water, which produces hydrogen (H2) gas, will compete with the reduction of the cation. Only the reaction with the higher (more positive) potential will occur. Keep in mind that the potentials for the oxidation reaction have the opposite sign as those for the corresponding reduction reactions. For example, the oxidation reaction Ag(s)→Ag++e− would have an E∘ox of −0.80 V. What is produced at each electrode in the electrolysis of NaBr(aq)?

Answer 1

Answer:

At anode - ${Br_2}_{(l)}$

At cathode - ${H_2}_{(g)}$

Explanation:

Electrolysis of NaBr:

Water will exist as:

$H_2O\rightleftharpoons H^++OH^-$

The salt, NaBr will dissociate as:

$NaBr\rightarrow Na^++Br^-$

At the anode, oxidation takes place, as shown below.

${Br^-}_{(aq)}\rightarrow {Br_2}_{(l)}+2e^-$

At the cathode, reduction takes place, as shown below.

$2{H^+}_{(aq)}+2e^-\rightarrow {H_2}_{(g)}$