CAIE IGCSE Chemistry – Gas & Other Tests (Alt to Practical): quick-reference for gas tests (NH₃, CO₂, Cl₂, H₂, O₂, SO₂) with expected results, plus tests for water, alkenes/alkanes, acids, and bases.  Includes syllabus note: Gas Test Reference Sheet is provided only in Papers 5 & 6 (2023–2025).