What substance is produced at the cathode during the electrolysis of molten calcium bromide, CaBr2? Assume standard conditions.

During the electrolysis of molten calcium bromide (CaBr2) at the cathode (negative electrode), the substance produced is pure elemental calcium (Ca).

This reaction occurs due to the reduction of calcium ions (Ca2+) present in the molten electrolyte. At the cathode, the Ca2+ ions gain two electrons (2e-) and undergo reduction to form elemental calcium (Ca). The overall reaction can be represented as follows:

Ca2+ + 2e- -> Ca

Under standard conditions, i.e., standard temperature (25°C) and pressure (1 atm), with a molten electrolyte of calcium bromide (CaBr2), only pure elemental calcium would be produced at the cathode.

To determine the substance produced at the cathode during the electrolysis of molten calcium bromide (CaBr2), we need to understand the process of electrolysis and the behavior of ions.

During electrolysis, an electric current is used to break down a compound into its constituent elements or ions. The compound being electrolyzed is called the electrolyte.

In the case of molten calcium bromide (CaBr2), it dissociates into calcium ions (Ca2+) and bromide ions (Br-) when heated to its melting point. During electrolysis, these ions will migrate towards the electrode of opposite charge.

At the cathode (negative electrode), positively charged cations are attracted. In this case, it's the calcium ions (Ca2+). The calcium ions receive electrons and get reduced, causing a reaction at the cathode.

To determine the substance produced at the cathode, we need to consider the reduction potential values of the ions present. The ion with the lower reduction potential will be favored for reduction at the cathode.

Looking up the reduction potential values, we find that calcium ions have a lower reduction potential compared to bromide ions. This means calcium ions are more easily reduced than bromide ions.

Therefore, during the electrolysis of molten calcium bromide, CaBr2, at the cathode, calcium ions (Ca2+) will be reduced to form elemental calcium (Ca).

The overall reaction at the cathode can be represented as:

Ca2+ + 2e- → Ca

Hence, the substance produced at the cathode during the electrolysis of molten calcium bromide is elemental calcium (Ca).

Ca and Br2

Ca at the - electrode; Br2 at the + electrode. In electrolysis, the cathode is negative.