Sub-topic 1
2026 · National One-Eighth
Free
Buffer solution ph: henderson-hasselbalch equation (true/false)
Read past contest →
Sub-topic 2
2026 · National Preliminary
Premium
Buffer solution ph: henderson-hasselbalch equation
Read past contest →
Sub-topic 3
2026 · National Preliminary
Premium
Buffer solution ph: henderson-hasselbalch equation
Read past contest →
Sub-topic 4
2026 · National One-Eighth
Premium
Ph of a strong diprotic base solution
Read past contest →
Sub-topic 5
2025 · National Quarterfinal
Premium
Ph of a saturated sparingly-soluble metal hydroxide
Read past contest →
Sub-topic 6
2023 · National One-Eighth
Premium
Acid strength, dilution and replaceable hydrogen (true/false)
Read past contest →
Sub-topic 7
2023 · National Preliminary
Premium
Ph of a weak monoprotic acid solution from its molarity and pka
Read past contest →
Sub-topic 8
2026 · National Preliminary
Premium
Ph of a weak monoprotic acid solution from its molarity and pka
Read past contest →
Sub-topic 9
2026 · National Preliminary
Premium
Composition and behaviour of buffer solutions (true/false)
Read past contest →
Sub-topic 10
2024 · National One-Eighth
Premium
Ph of a strong diprotic base solution from a given mass and volume
Read past contest →
Sub-topic 11
2023 · National Final
Premium
Minimum volume of water needed to dilute an acidic product to a target ph
Read past contest →
Sub-topic 12
2026 · National One-Eighth
Premium
Comparing a weak and strong acid of equal concentration: metal reaction, dilution, and titration (true/false)
Read past contest →
Sub-topic 13
2026 · National Preliminary
Premium
Acidic, basic or neutral nature of aqueous salt solutions from their parent acid/base strength (true/false)
Read past contest →
Sub-topic 14
2026 · National Preliminary
Premium
Riddle: phenolphthalein, an acid-base indicator
Read past contest →
Sub-topic 15
2025 · National Preliminary
Premium
Identifying salts as neutral or acidic from their parent acid and base (true/false)
Read past contest →
Sub-topic 16
2023 · National Preliminary
Premium
Molecular formula of the conjugate base of an alcohol, carboxylic acid, or phenol
Read past contest →
Sub-topic 17
2023 · National Preliminary
Premium
Problem of the day: ph, percentage dissociation and buffer formation for a weak monobasic acid
Read past contest →
Sub-topic 18
2022 · National Preliminary
Premium
Conjugate acid and conjugate base of a given species
Read past contest →
Sub-topic 19
2025 · National One-Eighth
Premium
Bronsted-lowry vs arrhenius bases, and temperature/dilution effects on acid ph and ionization (true/false)
Read past contest →
Sub-topic 20
2014 · National Final
Premium
Ph of beer (true/false)
Read past contest →
Sub-topic 21
2014 · National Final
Premium
Ph of human gastric contents (true/false)
Read past contest →
Sub-topic 22
2014 · National Final
Premium
Ph of human milk (true/false)
Read past contest →
Sub-topic 23
2017 · National Quarterfinal
Premium
Lower pka, not higher, indicates a stronger acid (true/false)
Read past contest →
Sub-topic 24
2017 · National Quarterfinal
Premium
Solutions with ph equal to zero do exist (true/false)
Read past contest →
Sub-topic 25
2017 · National Quarterfinal
Premium
Strong acids have weak conjugate bases (true/false)
Read past contest →
Sub-topic 26
2020 · National Preliminary
Premium
Comparing the acid strength of chlorous and chloric acid
Read past contest →
Sub-topic 27
2020 · National Preliminary
Premium
The main factor making chloric acid stronger than chlorous acid
Read past contest →
Sub-topic 28
2021 · National Semifinal
Premium
Arrhenius acids raise [h+] in water, while bronsted-lowry acids donate a proton in any medium
Read past contest →
Sub-topic 29
2022 · National Preliminary
Premium
True or false: a weak acid's dissociation constant is independent of temperature at constant concentration
Read past contest →
Sub-topic 30
2022 · National Preliminary
Premium
True or false: a weak acid's dissociation constant is lower at lower concentration
Read past contest →
Sub-topic 31
2022 · National Preliminary
Premium
True or false: a weak acid's dissociation constant is higher at lower concentration
Read past contest →
Sub-topic 32
2022 · National Preliminary
Premium
True or false: formate (cho2-) is a stronger base than acetate (c2h3o2-)
Read past contest →
Sub-topic 33
2022 · National Preliminary
Premium
True or false: fluoride is a stronger base than chloride
Read past contest →
Sub-topic 34
2022 · National Preliminary
Premium
True or false: hypochlorite (clo-) is a stronger base than chloride (cl-)
Read past contest →
Sub-topic 35
2022 · National Preliminary
Premium
True or false: a brønsted-lowry acid always contains at least one hydrogen atom
Read past contest →
Sub-topic 36
2022 · National Preliminary
Premium
True or false: a compound without hydroxide ion cannot be a brønsted-lowry base
Read past contest →
Sub-topic 37
2022 · National Preliminary
Premium
True or false: a brønsted-lowry acid may accept more than one proton
Read past contest →
Sub-topic 38
2022 · National Preliminary
Premium
Identifying the stronger acid when cn⁻+h2o⇌hcn+oh⁻ lies far right
Read past contest →
Sub-topic 39
2022 · National Preliminary
Premium
Identifying the stronger acid when h2s+nh2⁻⇌hs⁻+nh3 lies far left
Read past contest →
Sub-topic 40
2022 · National Preliminary
Premium
Identifying the stronger base when h2so4+cl⁻⇌hcl+hso4⁻ lies far left
Read past contest →
Sub-topic 41
2023 · National Preliminary
Premium
Sodium phosphate solution is basic (weak acid, strong base salt)
Read past contest →
Sub-topic 42
2023 · National Preliminary
Premium
Strontium nitrate solution is neutral (strong acid, strong base salt)
Read past contest →
Sub-topic 43
2023 · National Preliminary
Premium
Ammonium ethanoate solution is neutral (weak acid, weak base with similar ka/kb)
Read past contest →
Sub-topic 44
2023 · National Preliminary
Premium
Strongest and weakest acids among hbro, hbr, hbro2
Read past contest →
Sub-topic 45
2023 · National Preliminary
Premium
Strongest and weakest acids among hclo, hbro, hio
Read past contest →
Sub-topic 46
2023 · National Preliminary
Premium
Strongest and weakest acids among hclo, hclo2, hclo3
Read past contest →
Sub-topic 47
2023 · National One-Eighth
Premium
True or false: a weak acid and a weak base alone constitute a buffer system
Read past contest →
Sub-topic 48
2023 · National One-Eighth
Premium
True or false: an acid and the conjugate base formed from that weak acid constitute a buffer system
Read past contest →
Sub-topic 49
2023 · National One-Eighth
Premium
True or false: a lower-pka weak acid always forms a more acidic buffer than a higher-pka one
Read past contest →