9189051
Description
Flashcards by Emily Hargreaves, updated more than 1 year ago
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Created by Emily Hargreaves
almost 7 years ago
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| Question | Answer |
| TESTS FOR GASES | ... |
| Test for Ammonia | - Use damp red litmus paper (or universal indicator) --> goes blue - Place hydrochloric acid close by --> White smoke of aluminium chloride (irritant) forms. |
| Test for Carbon Dioxide | - Use lime water --> a white precipitate of of calcium carbonate forms which, in time, goes colourless as calcium hydrogen carbonate forms. |
| Test for Chlorine | - Damp blue litmus paper goes red on formation of chloric (I) acid. This then bleaches the paper. |
| Test for Hydrogen | - Add a lighted splint --> if the hydrogen is mixed with air there is a 'pop' but if the gas is pure, it catches fire, ad there is no 'pop'. |
| Test for Hydrogen Chloride | - Damp blue litmus paper (or universal indicator) --> goes red. - Place concentrated ammonia solution close by --> white smoke of ammonium chloride forms. |
| Test for Nitrogen Dioxide | - Observe colour. Nitrogen dioxide is the only BROWN GAS. |
| Test for Oxygen | - Add a glowing splint --> This relights the glowing splint, sometimes with a 'pop'. |
| TESTS FOR ORGANIC FUNCTIONAL GROUPS | ... |
| Test for Primary and Secondary alcohols | Potassium dichromate (VI) test - To 5 drops of the alcohol add 10 drops of 1M sulfuric acid and 4 drops of 0.1M potassium dichromate (VI) solution. Place the solution in boiling hot water from a kettle COLOUR CHANGE: Orange --> Green |
| Test for Aldehydes and Ketones | TOLLENS REAGENT - On warming Tollen's reagent with an aldehyde --> a silver mirror forms FEHLING'S SOLUTION - Add 5 drops of the aldehyde or ketone to 2cm3 of Fehling's solution. Aldehyde: Blue solution --> Red precipitate (Neither show a change with Ketones) |
| Test for Carboxylic acids | - Add 2M ammonia solution to 0.1M iron (III) chloride solution until a precipitate just appears. Now add more of the original iron (III) chloride in drops with stirring until the precipitate just dissolves. - Add this to the liquid under test and look for a RED SOLUTION. |
| Test for Phenol | - To the phenol add neutral iron (III) chloride solution COLOUR CHANGE: brown --> purple |
| TESTS FOR POSITIVE IONS | ... |
| Flame Tests | > Barium ions --> Greenish flame > Calcium ions --> Brick red flame > Copper (II) ions --> Bluish flame > Lead (II) ions --> White flame > Lithium --> Crimson red flame > Potassium ions --> Lilac flame > Rubidium ions --> Blue flame > Strontium ions --> Crimson flame > Sodium ions --> Persistent yellow flame |
| Add Sodium hydroxide solution | > Aluminium ions --> White precipitate which dissolves in excess alkali > Ammonium ions --> No precipitate, but odour of ammonia > Barium ions --> White precipitate >Calcium ions --> White precipitate > Copper (II) ions --> Blue precipitate > Iron (II) ions --> Green precipitate > Iron (III) ions --> Brown precitate > Magnesium ions --> White precipitate > Potassium ions --> No precipitate > Sodium ions --> No precipitate |
| Test for Ammonium ions | - Warm 0.4M sodium hydroxide solution with the test solution --> Ammonia gas will be given off. |
| Test for Copper (II) ions | - A blue precipitate forms when ammonia solution which dissolves n excess ammonia to give a deep blue solution. |
| Test for Lead (II) ions | - Forms a bright yellow precipitate when added to 0.1M solution of potassium iodide. |
| TESTS FOR NEGATIVE IONS | ... |
| Test for Carbonate ions | - Add hydrochloric acid --> produces lots of fizzing (Carbon dioxide identifiable with lime water). |
| Test for Bromide ions | - Forms a CREAM precipitate with silver nitrate solution which dissolves after the addition of CONC. Ammonia. |
| Test for Chloride ions | - Forms a WHITE precipitate with silver nitrate solution which dissolves after the addition of 2M Ammonia solution. |
| Test for iodide ions | - Forms a YELLOW precipitate with silver nitrate solution which is insoluble after the addition of 2M Ammonia solution. |
| Tests for Nitrate (V) ions | - Brown ring test --> Dissolve the Nitrate (V) in about 1ml of water and add 0.5g of iron (II) sulfate(VI)-7-water. Hold the test tube at an angle and carefully pour about 1ml of conc. sulfuric(VI) acid down te side of the test tube so it forms a layer at the bottom. A brown ring indicates nitrate(V) ions present. - Devada's alloy --> Add 2ml of nitrate (v) to 5ml of 1M sodium hydroxide solution. Add a little Devada's alloy and warm. Test for ammonia gas. |
| Test for Sulfate (VI) ions | - Forms a white precipitate with barium chloride (deionised water and dissolved oxygen.) |
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