CIE Nov 2016 v4 Paper 3 Q3

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PMT Qualitative Analysis At each stage of any test you are to record details of the following.colour changes seen the formation of any precipitate the solubility of such precipitates in an excess of the reagent added Where gases are released they should be identified by a test, described in the appropriate place in your observations. You should indicate clearly at what stage in a test a change occurs. No additional tests for ions present should be attempted. If any solution is warmed, a boiling tube MUST be used. Rinse and reuse test-tubes and boiling tubes where possible. Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given. (a) (i) Half fill the 250 cm3 beaker with water. Heat the water to about 80 C and then turn off the Bunsen burner. This is the hot water bath needed in the following tests. To a 34 cm depth of aqueous silver nitrate in a test-tube, add a few drops of aqueous sodium hydroxide to give a grey / brown precipitate. Then add aqueous ammonia dropwise until the precipitate just disappears. This solution is Tollens reagent and is needed in a following test.UCLES 2016 9701/34/O/N/16 [Turn over<br /> FB 5, FB 6 and FB 7 are each known to be one of ethanol, propanal and propanone. Carry out the following tests and complete the table. test FB 5 observations FB 6 FB 7 PMT To a 1 cm depth in a test-tube, add a few drops of acidified potassium manganate(VII) and place in the hot water bath. To a 0.5 cm depth in a test-tube, add a 1 cm depth of aqueous potassium iodide and a 1 cm depth of sodium chlorate(I). (This gives the same result as adding iodine and alkali.) To a few drops in a test-tube, add a 1 cm depth of Tollens reagent and place in the hot water bath. Leave for several minutes. (ii) Use these observations to identify the unknown compounds. FB 5 isFB 6 isFB 7 is(iii) Choose another reagent that would give a similar result for propanal and propanone but a different result for ethanol. Do not carry out this test. reagentresult for propanal and propanoneresult for ethanol(iv) Choose another reagent that would give a similar result for ethanol and propanone but a different result for propanal. Do not carry out this test. reagentresult for ethanol and propanoneresult for propanal[8]UCLES 2016 9701/34/O/N/16<br /> PMT (b) FB 8 contains one cation and one anion from those listed on pages 10 and 11. You are provided with solid FB 8 and an aqueous solution of FB 8. (i) To a 1 cm depth of aqueous FB 8 in a test-tube add a 1 cm depth of aqueous sodium hydroxide. Keep the test-tube and contents for test (ii). observation(ii) Transfer the contents of the test-tube from test (i) into a boiling tube and heat gently and carefully. Allow to cool and keep the boiling tube and contents for test (iii). observation(iii) Transfer a 1 cm depth of the mixture from test (ii) into a boiling tube and add a 2 cm depth of dilute hydrochloric acid. Heat gently and carefully. observationAllow to cool and keep the boiling tube and contents for test (iv). (iv) To the boiling tube from test (iii) add a piece of aluminium foil. Leave the boiling tube to stand. observation(v) Place a small spatula measure of solid FB 8 in a hard-glass test-tube and heat it gently at first and then more strongly. Identify two gases, other than water vapour, that are produced and give your evidence. identityevidenceidentityevidence(vi) From your observations in (i) to (v), write the formula of FB 8.(vii) Write the ionic equation for the reaction that is occurring in test (i). Include state symbols.[7]UCLES 2016 9701/34/O/N/16 [Total: 15] [Turn over<br />

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