Which ions are formed during electrolysis of water?
During the electrolysis of water, the water molecules (H2O) are broken down into hydrogen ions (H+) and hydroxide ions (OH-). This process occurs due to the passage of an electric current through the water.
To understand how the ions are formed during electrolysis of water, we need to take into account the two electrodes used in the process: the anode (positive electrode) and the cathode (negative electrode).
At the anode:
At the anode, oxidation takes place. Water molecules lose electrons and are broken down into oxygen gas (O2), hydrogen ions (H+), and electrons (e-). The chemical equation for this reaction is:
2H2O(l) -> O2(g) + 4H+(aq) + 4e-
At the cathode:
At the cathode, reduction occurs. The hydrogen ions (H+) attracted to the cathode accept electrons and are reduced to hydrogen gas (H2). The chemical equation for this reaction is:
4H+(aq) + 4e- -> 2H2(g)
Overall, the balanced chemical equation for the electrolysis of water can be represented as:
2H2O(l) -> 2H2(g) + O2(g)
So, during electrolysis of water, the ions formed are hydrogen ions (H+) and hydroxide ions (OH-). However, the hydroxide ions (OH-) are not released as a gas due to their reactivity with the anode.