Sub-topic 1
2026 · National One-Eighth
Free
Complex ions: oxidation states and coordination number of central metals
Read past contest →
Sub-topic 2
2025 · National Preliminary
Premium
Complex ions: oxidation states and coordination number of central metals
Read past contest →
Sub-topic 3
2026 · National Preliminary
Premium
Colours of common transition metal ions in aqueous solution
Read past contest →
Sub-topic 4
2026 · National Preliminary
Premium
Physical state and color of the halogens (cl2, br2, i2) at room temperature
Read past contest →
Sub-topic 5
2012 · National Preliminary
Premium
Color of the precipitate from potassium hexacyanoferrate(ii) and iron(iii)
Read past contest →
Sub-topic 6
2014 · National Quarterfinal
Premium
Boiling calcium hydrogencarbonate solution precipitates calcium carbonate (true/false)
Read past contest →
Sub-topic 7
2016 · National One-Eighth
Premium
The iron(iii) hydroxide precipitate is insoluble in excess ammonia (true/false)
Read past contest →
Sub-topic 8
2016 · National One-Eighth
Premium
Calcium sulfide is soluble, giving no precipitate with h2s (true/false)
Read past contest →
Sub-topic 9
2016 · National Preliminary
Premium
Moles of h2s gas from hydrolysis of aluminium sulfide
Read past contest →
Sub-topic 10
2016 · National Preliminary
Premium
A reddish-brown vapor with conc. h2so4 suggests a nitrate is present, not any generic solid (true/false)
Read past contest →
Sub-topic 11
2016 · National Preliminary
Premium
A cream precipitate with agno3 indicates a bromide halide (true/false)
Read past contest →
Sub-topic 12
2016 · National Preliminary
Premium
Only iodide, not chloride or bromide, gives a yellow precipitate with pb2+ (true/false)
Read past contest →
Sub-topic 13
2017 · National Quarterfinal
Premium
Dilute ammonia does not precipitate calcium hydroxide from calcium ion solution (true/false)
Read past contest →
Sub-topic 14
2017 · National Quarterfinal
Premium
H2s precipitates zinc sulfide but not a stable aluminium sulfide in aqueous solution (true/false)
Read past contest →
Sub-topic 15
2021 · National Quarterfinal
Premium
True or false: ca2+ solutions give no precipitate with dilute naoh or h2s
Read past contest →