Electrolysis is a powerful technique used to break down a substance by electricity. Electrolysis only occurs when an ionic substance is molten or is in a solution. This liquid substance is called an electrolyte.

Authors Avatar

BACKGROUND:-

Electrolysis is a powerful technique used to break down a substance by electricity. Electrolysis only occurs when an ionic substance is molten or is in a solution. This liquid substance is called an electrolyte.

Electrolytes are made up of ions. They are molten or in a solution so that the ions are free to move. The ions present are attracted to the electrode with the opposite charge:

  • Positive ions are attracted to the cathode (negative electrode).
  • Negative ions are attracted to the anode (positive electrode).

As this is happening, a redox reaction is taking place. A redox reaction is when oxidation and reduction happen simultaneously. When a substance is oxidised it loses electrons, when a substance is reduced it gains electrons.

  • At the anode, the negative ions lose electrons and are oxidised.
  • At the cathode, the positive ions gain electrons and are reduced.

In the experiment, sulphuric acid was added to the water to form an acidic solution because pure water is unable to conduct electricity. This is because the charges are balanced. Sulphuric acid (H2SO4) forms ions in water:

                H2SO4 (aq)  →  2H+ (aq)  +  SO42- (aq)

In the dilute solution there are these atoms present:

H+ and  SO42-  from sulphuric acid,  H+  and OH-  from water

CIRCUIT DIAGRAM:-

AIM:-

The aim of the experiment is to investigate factors which affect the size of the current which flows through during electrolysis.

I have chosen to find out about the effect of:

  • varying the distance between the electrodes
  • varying the depth of the electrodes in the dilute acid

METHOD:-

The method for the experiments was provided. However, in order to ensure that the experiment was kept fair and that the results obtained would be accurate, certain variables which could also affect the current flow have to be kept constant. These are:

  • the time that each electrode is kept in the dilute acid
  • the voltage from the power pack
  • the temperature of the solution
  • the molarity/concentration of the acid
  • the amount of acid used
  • the size of the electrodes
Join now!

PREDICTION:-

I predict that as the distance between the electrodes increases, the amount of current flowing will decrease. I think this because the further that the electrodes are apart the greater the resistance will be between them, making it more difficult for the current to pass. This theory is justified by looking at the formula; current = voltage ÷ resistance. The physics rule, ‘the longer the length of wire, the greater the resistance’, can be applied to the path of the current when passing through the electrolyte. As the distance between the two electrodes increases, the resistance ...

This is a preview of the whole essay