3.1Ba Tests for simple ions
| ion | formula | test | result |
| carbonate | CO32- | add dil HCl(aq) add group two ions |
CO2 detected white precipitate |
| hydrogen carbonate | HCO3- | add dil HCl(aq) add any metal ions |
CO2 detected no precipitate formed |
| sulfate (VI) | SO42- | BaCl2(aq) to solution then add dil HCl(aq) | thick white precipitate insoluble in acid |
| sulfite | SO32- | add dil HCl(aq) add BaCl2(aq) to solution then add dil HCl(aq) |
SO2 detected white ppt soluble in acid |
| chloride | Cl- | add HNO3(aq) + AgNO3(aq) to solution | white precipitate soluble in dilute ammonia solution |
| bromide | Br- | add HNO3(aq) + AgNO3(aq) to solution | buff precipitate soluble in conc. ammonia solution |
| iodide | I- | add HNO3(aq) + AgNO3(aq) to solution | yellow precipitate insoluble in conc. ammonia solution |
| nitrate | NO3- | heat with Al + NaOH(aq) | ammonia detected |
| ammonium | NH4+ | heat NaOH(aq) | ammonia detected |
| lithium | Li+ | flame test | crimson red flame |
| sodium | Na+ | flame test | yellow flame |
| potassium | K+ | flame test | lilac flame |
| magnesium | Mg2+ | add NaOH(aq) | faint white precipitate |
| calcium | Ca2+ | flame test | brick red flame |
| strontium | Sr2+ | flame test | scarlet red flame |
| barium | Ba2+ | flame test | apple green |
sodium, potassium, lithium, sodium, calcium barium
3.1Bb Tests for simple gases
| gas | formula | test | result |
| hydrogen | H2 | lighted splint | burns with squeaky pop |
| oxygen | O2 | glowing splint | relights |
| carbon dioxide | CO2 | bubble through limewater | limewater turns milky |
| ammonia | NH3 | smell damp litmus Conc HCl at mouth of bottle |
pungent red litmus turns blue white smoke forms |
| chlorine | Cl2 | smell damp litmus |
swimming pool smell blue litmus turns red then is bleached |
| nitrogen dioxide | NO2 | colour smell damp litmus |
brown acrid blue litmus turns red |
| sulfur dioxide | SO2 | smell damp litmus dichromate paper |
acrid blue litmus turns red from orange to green/blue |
3.1Bc
3.1Bd Distillation and heating under reflux
3.1Be Interpretation of group 1,2, 7 and some organic chemistry
sulfate solubility- If a solution of any sulfate is added to a solution of a group 2 metal compound then a precipitate is likely.
| group 2 ion in solution | effect of adding a sulfate solution |
| Mg2+ | no precipitate MgSO4 is soluble |
| Ca2+ | white precipitate of CaSO4 |
| Sr2+ | white precipitate of SrSO4 |
| Ba2+ | white precipitate of BaSO4 |
Hydroxide solubility - If sodium hydroxide is added to a solution of a group 2 compound then a precipitate is likely.
| group 2 ion in solution | effect of adding a hydroxide solution |
| Mg2+ | faint white precipitate of Mg(OH)2 |
| Ca2+ | faint white precipitate of Ca(OH)2 |
| Sr2+ | faint white precipitate of Sr(OH)2 on standing |
| Ba2+ | no precipitate, Ba(OH)2 is soluble |
heating carbonates and nitrates
| substance | effect of heat |
| lithium and all group 2 carbonates | carbon dioxide detected |
| sodium and potassium carbonates | no effect (except water of crystallisation may be given off) |
| sodium and potassium nitrates | oxygen only gas evolved |
| lithium and all group 2 nitrates | nitrogen dioxide and oxygen evolved |
Halogens
| substance | formula | test | positive result |
| chlorine | Cl2 | smell damp litmus |
swimming pool smell blue litmus turns red then is bleached |
| bromine | Br2 | colour (aqueous) colour (volasil) smell damp litmus |
orange/red red acrid blue litmus turns red |
| iodine | I2 | colour (aqueous) colour (volasil) add aqueous starch |
brown pink from colourless to blue/black |
Organic analysis
| functional group | test | observation for positive test |
| alkene alkene |
shake with bromine solution shake with acidified (H2S04) manganate(VII) |
yellow solution is decolourised purple solution is decolourised |
| halogenoalkane | warm with aqueous NaOH acidify with aqueous HNO3 add aqueous AgNO3 |
white ppte, chloro compound cream ppte, bromo compound yellow ppte, iodo compound |
| hydroxyl group -OH | add PCl5(s) | steamy white fumes |
3.1Bf Interpretation of qualitative and quantitative results
Calculate concentrations from volumetric titration results.
Calculate enthalpy changes from thermochemical experimental results.
Identify ions and organic functional groups from the results of tests.
3.1Bg Devising and planning simple experiments
3.1Bh Evaluating errors in quantitative experiments
3.1Bi Comment critically on experimental procedures
3.1Bj Comment on safety aspects
of experiments.
Safety considerations should relate to specific experiments not be of a general
nature.