Chemical Effect of Current

There are various uses of electricity in our daily life. We use electricity to light our homes, heat our rooms, to electroplate metals and many more. While using electricity we are basically converting electrical energy to various forms according to our need. These conversions of energy can also be regarded as effect of electricity. There are various effects of current and we will talk about two of those in here.

Chemical effect:

When current passes through the metal it produces heating and lighting effect. But what happens when electricity is passed through a liquid. Depending on liquid the effect differs. There are liquids that can conduct electricity and there are some that cannot. Water in its pure state cannot conduct electricity but if we add either acid or base or salt to it, water can conduct electricity. We will learn two different chemical effect of current:

Electrolysis:

The process of electricity conduction in liquid is called electrolysis. The process of electrolysis is possible due to presence of ions in the liquid. If a liquid cannot disassociate into ions then it cannot conduct electricity. For the process of electrolysis, we have to have a source of electricity (batteries) two rods that can carry electricity (anode (rod connected to the positive terminal of the battery) and cathode (rod connected to the negative terminal of the battery)) and solution that can carry electricity.

Electrolysis of Water:

For electrolysis of water we have to take a battery (as a source of current), two graphite rods (one as anode and another as cathode) and wire to connect to rods and battery. As we already know water in pure state is a non-conductor, so we add sulphuric acid in the water. Now we will have ions in the liquid to conduct electricity. Water will break down into hydrogen ion (H⁺) and hydroxyl ion (OH^-) and sulphuric acid will also break into hydrogen ion (H⁺) and sulphate ion (SO2^--). This electrolysis of water will give you hydrogen gas at the cathode and oxygen gas in the anode. (Remember the output of the electrolysis differs according to the choice of solute in the water. If you choose NaCl i.e. table salt then you will get hydrogen at cathode and chlorine gas at anode) hen electricity is passed the following reaction occurs:

At Cathode:

2H⁺(aq) + 2e^- → H₂(g)

At Anode:

4OH^-(aq) – 4e^- → 4OH

4OH (aq) → 2H₂O (l) + O₂(g)

Points to remember while doing electrolysis of water:

1. The solvent used to make water conductive must be H₂ SO₄ if you want to get hydrogen and oxygen as products. If you use hydrochloric acid or table salt the products will differ.
2. The cathode and anode must be graphite rods (or any other non-reactive material) or else the output of electrolysis will differ.

Electroplating:

The process of laminating one metal to the other using electricity is called electroplating.It is similar to the electrolysis process as it requires a liquid medium that conducts electricity and a source of electricity and two rods that can act as cathode and anode. But in the process of electrolysis we use metal from anode to plate into the metal in cathode. Here products at anode and cathode do not have any importance rather metal from anode gets thinner as it gets plated on the metal in cathode. We are going to discuss electroplating of copper on iron nail.

To start the process we need an iron nail and a copper rod. The electrolyte we are going to use is copper sulphate (CuSO₄). Copper sulphate in water disassociates into copper ion (Cu⁺⁺) and sulphate ion (SO₄^--). When current is passed through the setup then following reactions occur:

At Cathode:

Cu⁺⁺+ 2e^-→ Cu (Electroplated into iron)

At Anode:

Cu → Cu⁺⁺+ 2e^-(This cupper ion goes into solution so amount of Cu is reduced)

Electroplating stops when all the metal from anode is plated to anode.

Points to remember while electroplating:

1. The metal being plated should always be at cathode and the metal gets plated is at the anode.
2. The salt used in the solvent must be the salt of the anode metal.

Interrelation between electricity and magnetism

Ostered discovered that electric current flowing through a conductor produced a magnetic effect around it. Micheal Faraday discovered that it was possible to obtain electric current in a circuit from a magnetic field.

Magnetic Flux and its Variation

Magnetic lines of force start from N- pole To S-pole. Internally these magnetic lines of force move from S-pole to N-pole. Magnetic lines of force are always closed. Magnetic lines through a surface of magnetic lines of force passing the surface held perpendicular to these lines of force.