Criado por Stephen Cole
mais de 10 anos atrás
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Questão | Responda |
Name a reagent you could use to show that sulphate ions were present in a solution. State the observation you would make if the test was positive and identify the substance responsible for this observation. | Barium chloride White precipitate Barium sulphate |
Name a reagent you could use to show that chloride ions are present in a solution. State the observation you would make if the test was positive. Identify the substance responsible for this observation. | Acidified silver nitrate White precipitate Silver chloride |
State the trend in the solubility of the silver halides in ammonia going down group 7. Hence describe a test to distinguish between AgCl, AgBr and AgI. | Decreases Add dilute ammonia - AgCl will dissolve, others will not Add concentrated ammonia - AgBr will dissolve, AgI will not |
Name a reagent you could use to show that bromide ions are present in a solution. State the observation you would make if the test was positive. Identify the substance responsible for this observation. | Acidified silver nitrate Cream solution Silver bromide |
Name a reagent you could use to show that iodide ions are present in a solution. State the observation you would make if this test was positive. Identify the substance responsible for this observation. | Acidified silver nitrate Yellow precipitate Silver iodide |
Suggest why it is not possible to use acidified silver nitrate to show that fluoride ions are present in a solution in the way it is used to test for other halides. | Silver fluoride is soluble (so no precipitate would form) |
Name a reagent you could use to distinguish between an aldehyde and a ketone. State the observation you would make with an aldehyde and the observation you would make with a ketone. | Any of: Tollens' reagent Aldehyde: silver forms Ketone: no change Fehling's/Benedict's reagent Aldehyde: brick-red solid forms Ketone: no change Acidified potassium dichromate(VI) Aldehyde: orange to green Ketone: no change/remains orange |
State five observations you might make during the reactions between solid sodium iodide and concentrated sulfuric acid. In each case, identify the substance responsible. | Black solid - iodine Purple vapour - iodine Steamy fumes - hydrogen iodide Smell of bad eggs - hydrogen sulphide Yellow solid - sulphur |
State two observations you would make when solid sodium bromide is reacted with concentrated sulfuric acid. In each case, identify the substance responsible. | Steamy fumes - hydrogen bromide Brown fumes - bromine |
State one observation you would make when solid sodium chloride reacts with concentrated sulfuric acid. Identify the substance responsible. | Steamy fumes - hydrogen chloride |
State the observation you would make when chlorine is reacted with sodium bromide. Identify the substance responsible. | Orange-brown colour - bromine |
State the observation you would make when chlorine is reacted with sodium iodide. Identify the substance responsible. | Black/grey solid or red/brown solution - iodine |
Describe how you could test for chlorine gas. | Chlorine gas bleaches damp litmus paper |
Name a reagent you could use to show that an organic molecule contains a double bond. State the observation you would make if the test was positive. | Bromine water Orange/brown to colourless |
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