Electrolysis of Brine
Investigate the products of electrolyzing concentrated sodium chloride solution
setup
Cathode (-)
Anode (+)
DC POWER
12.0 V
Lab Guide
1Experiment Setup
- Place inert graphite electrodes in conc. NaCl
- Connect to DC power
2Electrolysis in Progress
- Turn on power supply to start electrolysis
- Observe the ion migration
3Testing Products
Click buttons to identify products:
- Cathode: Burning splint
- Anode: Moist blue litmus
- Solution: Phenolphthalein
4Experiment Summary
Drag products to the cathode, anode, and solution, then review the equations.
HKDSE Tip
- Ion migration:Cations (Na⁺, H⁺) move to the cathode; anions (Cl⁻, OH⁻) move to the anode.
- Solution change:As H⁺ is discharged, OH⁻ concentration increases and the solution becomes alkaline (NaOH forms).
- Anode gas test:Use moist blue litmus paper (not dry) near the anode.
💡 Checkpoint
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