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K223 / K225 / 2027
Qualitative Analysis

Chapter summary

Qualitative Analysis, at a glance

Identify hydrogen, oxygen and carbon dioxide with tests that tell them apart.

SEC G2 Science K223 / K225 (2027)

Quick revision

Revisit the essentials, then return to an explanation when you need it.

Hydrogen: a lighted splint gives a squeaky pop. Oxygen: a glowing splint relights. Carbon dioxide: limewater turns milky (a white precipitate). Name the test and its result first, then the gas.

Check your understanding

Which single test distinguishes oxygen from carbon dioxide?

  1. A lighted splint, which pops in oxygen but goes out in CO2
  2. A glowing splint, which relights in oxygen but goes out in CO2
  3. Limewater, which turns milky in oxygen but stays clear in CO2
Show the answer

A glowing splint, which relights in oxygen but goes out in CO2

Oxygen relights a glowing splint; carbon dioxide puts it out. Confirm CO2 with limewater, which turns milky.

Quick recall

Card 1 of 6. Answer in your head, then check.

Describe the test for hydrogen.

Revisit an explanation

Read the full chapter