Electrolysis of Sodium Chloride (NaCl).
Aim: To find out how the exchange of NaCl will affect the current.
Preliminary Test: To make sure we understand how the experiment is going to work, .
we need to carry out an initial test. This will enable us to go through.
the experiment and note the ways in which we can keep it a fair test. .
Preliminary results are roughly direct, they may double roughly to.
to the actual results due to human error etc.
Through doing this initial test we found that we can't use too much.
salt because it will be saturated (wont dissolve) and the current.
wont change, giving inaccurate results.
Prediction: I predict that the more NaCl added to H2O the higher the current will be.
I predict this because the more surface area and the more concentration .
would make more reactions, which would speed up the reaction and create .
a higher current.
Hypothesis: .
• Electrolysis is the decomposition of a compound using electricity.
• Electricity is the flow of electrons or charged particles known as IONS.
• When a salt (NaCl) is dissolved in water its ions are free to move.
• Water produces ions so the products may be different from when you electrolysed the molten salt.
• H20(l) H+(aq) + OH- (aq) .
.
The Ions present are: Na+, Cl-, OH- and H+.
.
At the Cathode: The ions present here are Na+ and H+. The most reactive ion is going .
stay in the solution. Looking at the reactivity series, Na+ (sodium) is .
more reactive than H (hydrogen) and so will remain in the solution, as hydrogen gas bubbles away.
2H+ + 2 e- H2 (g).
This is a REDUCTION reaction.
.
At the Anode: The ions present here are Cl- and OH-. Here, if a Halogen is present, .
Halogen gas is given off, if there is no Halogen, then oxygen gas.
is given off. Cl- ions give up electrons more willingly than OH- ions.
