electrolysis (Required Practical) Flashcards
1
Q
what are the steps to carry out electrolysis with copper 2 chloride
A
- pour 50cm cubed of copper 2 chloride solution into a beaker
- place a plastic petri dish over a beaker petri dish should have 2 holes
- insert a carbon graphite rod into each hole these are electrodes (Make sure that the 2 rods do not touch each other and produce a short circuit)
- attach crocodile leads to the rods and connect the rods to the terminals of a low voltage power supply
- set the power supply to 4 volts and turn it on
- look carefully at the 2 electrodes
- looking at the negative rod it is being coated in copper (Remember if the metal is less reactive then hydrogen then the metal will be discharged at the cathode)
- looking at the positive rod it will have bubbles of gas and have the smell of chlorine in the air
2
Q
why will the graphite rods not react
A
the electrodes are inert (electrodes will not react)
3
Q
what is the positive and negative electrode called
A
negative- cathode
positive- anode
4
Q
what happens when you carry out electrolysis on an aqueos solution containing a halide ion
A
the halogen is discharged at the anode
5
Q
what are the steps to carry out electrolysis with sodium chloride solution
A
- place 50cm cubed of sodium chloride solution into the beaker
- turn on the low voltage power supply and look at the 2 electrodes
- at the anode you will see bubbles being produced which bleaches blue litmus paper
- at the cathode you will also see gas which is hydrogen (because you are electrolysing sodium chloride solution which is more reactive than hydrogen
6
Q
what happens when you hold blue litmus paper near the anode proving what
A
It will be bleached proving that the chlorine gas is present
7
Q
what does sodium chloride contain
A
chloride ion which is a halide
8
Q
what does hydrogen react when it is put near a lit splint
A
it will make a squeaky pop
