What occurs during the electrolysis of aqueous solutions?

During the electrolysis of aqueous solutions, an electric current is passed through the solution to cause a chemical reaction.

Electrolysis is a process that uses an electric current to drive a non-spontaneous chemical reaction. In the context of aqueous solutions, this involves the breaking down of certain molecules within the solution into their constituent elements. The solution itself is often a salt dissolved in water, and the water can also be broken down into hydrogen and oxygen.

The process begins by setting up a circuit with a power source, two electrodes (usually made of an inert material like platinum or graphite), and the aqueous solution. The electrodes are immersed in the solution and connected to the power source. When the power is switched on, the electric current flows through the circuit.

The positive ions in the solution are attracted to the negative electrode (cathode), where they gain electrons (reduction). The negative ions are attracted to the positive electrode (anode), where they lose electrons (oxidation). This movement of ions constitutes the electric current in the solution.

For example, if the solution is copper sulfate, CuSO4, the copper ions (Cu2+) are attracted to the cathode where they gain electrons and deposit as copper metal. The sulfate ions (SO4 2-) are attracted to the anode, but water is preferentially oxidised producing oxygen gas.

The electrolysis of aqueous solutions is a key process in many industrial applications, including the production of chlorine and sodium hydroxide from brine (salt water), the purification of copper, and the production of hydrogen for fuel cells. It's also a fundamental concept in the study of chemistry, illustrating important principles about the nature of ions, electric current, and chemical reactions.