Oquizy

Both form white precipitates with sodium hydroxide. How can John distinguish them?

Add HCl – both turn blue Add more NaOH – aluminium dissolves, zinc does not Add more NaOH – zinc dissolves, aluminium does not Add NH₃ – both give brown precipitate

Xinyi has 3 test tubes each with gas samples: A (turns limewater milky), B (relights glowing splint), C (pungent smell turns red litmus blue). The labels are missing from the test tubes. Which gases are in tubes A, B, and C?

A: CO₂, B: H₂, C: NH₃ A: CO₂, B: O₂, C: NH₃ A: NH₃, B: CO₂, C: O₂ A: O₂, B: H₂, C: CO₂

Which reagent is best used to test for unsaturation in organic compounds?

Acidified potassium manganate(VII) Aqueous bromine Barium nitrate Dilute nitric acid

Zinc and lead both form white ppt with NaOH. How can they be distinguished?

Add excess NaOH: zinc dissolves, lead remains Add NaOH: only lead dissolves Add NH₃: only lead dissolves Flame test: both give red flame

John has a test tube containing a colourless solution. These are the observations he made
- White ppt forms with NaOH
- Precipitate dissolves in excess NaOH
- Add NH₃: white ppt again, also dissolves in excess. What cation is present?

Aluminium Calcium Lead Zinc

How does cold, acidified potassium manganate(VII) react with unsaturated compounds?

Bubbles are released Purple colour decolourises Purple colour remains Solution turns blue

Quiz: Chemistry - Qualitative Analysis