What is electrolysis used for

If a current flows through the substance when it is molten or dissolved, it is an electrolyte. Electrolysis Ionic substances contain charged particles called ions. This is what happens during electrolysis: Positively charged ions move to the negative electrode during electrolysis.

They receive electrons and are reduced. Negatively charged ions move to the positive electrode during electrolysis. They lose electrons and are oxidised. The electrode connected to the positive end is referred to as anode and that which is connected to the negative end is referred to as the cathode.

Electrodes help in the conduction of electrons into and out of the cell as well as provide the surface for electrode reactions. They are made up of electric conductors like metals or graphite. They may be in the form of rods or as a surface coating on the rods of other material or as a coating on the inside surface of the electrolytic cell. In general platinum and graphite are used in making electrodes. They are inert and do not participate in the electrolysis reactions. However, the former is very costly while the latter is cheaper.

In the electrolytic cell, the anode is denoted by a positive sign while the cathode is denoted by a negative sign. However, one should keep in mind that irrespective of whether it is an electrolytic cell or a galvanic cell, at the anode, an oxidation half reaction takes place while at the cathode the other half-reaction - reduction occurs. The electrodes may be divided into two types depending on how they are involved in the electrolytic process.

The electrodes made up of Noble metals like platinum are used as inert electrodes. These are either dissolved into the electrolyte or a substance is deposited on them.

The cell is filled with the melt or the aqueous solution of the electrolyte and is subjected to potential difference sufficient to drive the electrolysis.

The electrolyte is the substance that furnishes free ions either in the molten state or in the aqueous medium. What is electrolysis in chemistry?

During electrolysis, the free ions furnished by the electrolyte are migrated towards oppositely charged electrodes and are discharged under electric potential. Whereas, the anion, Y n- moves towards the anode and is oxidized to 'Y' by losing electrons. Thus electrolysis is a redox reaction. The reduction half-reaction occurs at the cathode, whereas the oxidation half-reaction occurs at the anode.

The entire process, otherwise non-spontaneous, is driven by the electromotive force. However, sometimes the solvent molecules or the electrodes may also participate in the electrolysis instead of the ions furnished by the electrolyte. The electrolytes are ionic compounds, which furnish free ions in the molten state. When ample electromotive force is applied, these free ions start migrating towards the electrodes and get discharged.

With the formation of neutral substances, the electrolyte is decomposed. So we can say that the decomposition of an electrolyte when electricity is passed through it is called electrolysis. Take some water in a plastic or glass vessel. Add a pinch of salt or a few drops of an acid such as vinegar to the water.

This will make the solution conduct electricity. Break open two cells and use their carbon rods as electrodes. Since carbon does not react easily, the electrodes do not undergo change during electrolysis.

Place the electrodes in the solution and connect them to a battery of 6 volts. Soon you will see bubbles of gas at the electrodes.

The gas evolved at the cathode is hydrogen and that at the anode is oxygen. Note that there are more bubbles at the cathode. The chemical change that takes place in this activity is called the electrolysis of water, in which water gets decomposed into hydrogen and oxygen.

These lose charge to form hydrogen and oxygen at the electrodes. It is clear that the volume of hydrogen liberated is twice that of oxygen. That is why you see more bubbles at the cathode. You can use electrolysis to make an electric pen. Dissolve some potassium iodide KI in a starch solution.

Soak a piece of stiff paper in this solution and place it on the bared end of a wire. Connect this wire to the negative terminal of a battery.

Use a wire connected to the positive terminal of the battery to write on the piece of paper. When electricity is passed through the solution, the iodide ions lose their charge to form iodine. Electroplating is an important use of electrolysis. The electrical process of coating an inexpensive conductor with a metal is called electroplating. Electroplating is done for protection or decoration. For example, the bumpers of cars are chromium-plated to protect them from corrosion.

For the same reason, water taps are plated with nickel or chromium. For electroplating a steel spoon with silver, a solution of a silver salt is taken as the electrolyte. The spoon and a silver bar are dipped into the electrolyte and connected to the negative and positive terminals of a battery respectively. The positively charged silver ions move to the negative electrode spoon and form a deposit of silver on it.