ELECTROLYSIS PRACTICAL

METHOD: COPPER CHLORIDE (CuCl2)

Add set volume of CuCl2 to a beaker
Add lid, insert electrodes through holes (electrodes no touch)
Connect electrodes to low power supply
Set power supply to 4V, switch it on
Few minutes turn power supply off + observe
Record observation at electrodes

METHOD: SODIUM CHLORIDE (NaCl)

Add set volume of NaCl to a beaker
Add lid, insert electrodes through holes (electrodes no touch)
Connect electrodes to low power supply
Set power supply to 4V, switch it on
Few minutes turn power supply off + observe
Record observations at the electrodes

SAFETY

Safety goggles
Well ventilated room, large quantities of chlorine gas is toxic

OBSERVATIONS OF COPPER CHLORIDE

CATHODE: Brown solids coating rod
ANODE: Bubbles of gas, litmus paper turns white

OBSERVATIONS OF SODIUM CHLORIDE

CATHODE: More rapid production of bubbles of gas
ANODE: Bubbles of gas, litmus paper turns white

What do these observations tell us

When Chlorine is produced, litmus paper turns white + bubbles of gas form.
When Hydrogen is produced, bubbles form more vigorously

RESULTS OF SODIUM CHLORIDE

ANODE: Chlorine formed
CATHODE: Hydrogen formed

RESULTS OF COPPER CHLORIDE

ANODE: Chlorine formed
CATHODE: Copper formed

Why is sodium not produced

Sodium is more reactive than hydrogen therefore hydrogen is produced

How can you test for chlorine

The gas produced will turn litmus paper white

How can you test for hydrogen gas

Hold a lighted splint, a sqeaky pop should be made

How can you test for oxygen gas

gas produced should relight a glowing splint