📖 Theory & Concepts▼

Electrolysis of Water

2H₂O(l) → electricity → 2H₂(g)↑ + O₂(g)↑
  • Cathode (−): Hydrogen gas (Hâ‚‚) — 2 volumes
  • Anode (+): Oxygen gas (Oâ‚‚) — 1 volume
  • Ratio: Hâ‚‚ : Oâ‚‚ = 2 : 1 by volume

Setup Details

Acidified water (with dilute Hâ‚‚SOâ‚„) is used to increase conductivity. Two platinum or graphite electrodes are used. Gases collect in inverted test tubes over each electrode.

Tests: H₂ — burns with a 'pop' sound. O₂ — relights a glowing splint.

🎯 Objective

Demonstrate that water is composed of hydrogen and oxygen by electrolysis, and confirm the 2:1 volume ratio.

Procedure
1

Fill Hofmann voltameter with acidified water.

2

Connect electrodes to battery/power supply.

3

Switch on current and observe gas bubbles.

4

Gas collects: Hâ‚‚ at cathode (2x), Oâ‚‚ at anode (1x).

5

Test gases: Hâ‚‚ pops, Oâ‚‚ relights a splint.

Ready — Switch on current
Hâ‚‚ Vol
0 mL
Oâ‚‚ Vol
0 mL
H₂ Cathode (−) O₂ Anode (+) DC Power
Lab Journal
Waiting for experiment...
Hâ‚‚ : Oâ‚‚ Ratio---
Hâ‚‚ Test---
Oâ‚‚ Test---