What are the products of electrolysing potassium iodide solution?
Product at cathode Product at anode
hydrogen iodine
hydrogen oxygen
potassium iodine
potassium oxygen
The products of electrolysing potassium iodide solution are hydrogen and iodine at the cathode, and oxygen and potassium iodide at the anode.
how?
When a solution of potassium iodide (KI) is electrolysed using an electric current, the positively charged potassium ions (K+) move towards the negative cathode, while the negatively charged iodine ions (I-) move towards the positive anode.
At the cathode, water molecules (H2O) are reduced by gaining electrons from the negatively charged cathode to form hydrogen gas (H2) and hydroxide ions (OH-). The hydroxide ions then react with the potassium ions present in the solution to form potassium hydroxide (KOH), which stays in solution.
2H2O + 2e- ---> H2 + 2OH-
2K+ + 2OH- ---> 2KOH
At the anode, the positively charged iodine ions are oxidised by losing electrons to form iodine molecules (I2) and oxygen gas (O2) from the water molecules (H2O) present in the solution. The released oxygen gas bubbles out of the anode.
2I- - 2e- ---> I2
2H2O ---> O2 + 4H+ + 4e-
Overall, the products of the electrolysis of potassium iodide solution are hydrogen gas at the cathode and iodine and oxygen gases along with potassium hydroxide at the anode.
The products of electrolysing potassium iodide solution depend on the reaction happening at each electrode.
At the cathode (negative electrode):
1. Hydrogen gas (H₂) is produced when water molecules (H₂O) undergo reduction:
2H₂O + 2e⁻ → H₂ + 2OH⁻
At the anode (positive electrode):
1. Iodine (I₂) is produced when iodide ions (I⁻) undergo oxidation:
2I⁻ → I₂ + 2e⁻
Therefore, the products of electrolysing potassium iodide solution are hydrogen gas (H₂) at the cathode and iodine (I₂) at the anode.