Investigate How Changing the Concentration of a Sodium Chloride Solution Affects the Rate of Electrolysis
During my investigation I will be investigating how changing the concentration of sodium chloride (NaCl) will affect the rate of electrolysis.
“Electrolysis is the process by which ionic substances are broken down into simpler substances using electricity. During electrolysis, metals and gases may form at the electrodes.” (http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/ions/electrolysisrev1.shtml)
There are always two electrodes during electrolysis; the anode, which has a positive charge, and the cathode, which has a negative charge). Generally, the electrodes are made of carbon as it is the only non-metal that is a conductor. The positively charged ions are attracted to the negative cathode where they gain electrons to form atoms that have no overall charge. The reaction at the cathode is a reduction reaction. The negatively charged ions are attracted to the positive anode where they lose electrons to form atoms that have no charge. The reaction at the anode is oxidation reaction. In the compound, sodium chloride, two gases should be formed; hydrogen and chlorine, they will then be released into the atmosphere.
To start the investigation I need to do some preliminary work. I need to decide what voltage to set the power pack at. If the voltage is increased the number of electrons in the circuit will increase, resulting in a higher current. To do this I tested three different voltages and I will use the one that produces the biggest range of results. The voltages I will test are 6, 4.5 and 3.
1. First set up the circuit as shown below.
2. Then, measure 50cm3 of NaCl solution using a measuring cylinder.
3. Turn on the power pack and set it to 6 volts.
4. Check the ammeter and record the measurement.
5. This needs to be repeated three times using the same quantity of solution...