CIE Nov 2013 v6 Paper 3 Q3

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Examiners For Use 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 identi ed 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) You will carry out further tests on the ions in FB 6.Put a spatula measure of FB 6 into a test-tube. Half fill the test-tube with distilled water and stir until the solid dissolves. Use a 1 cm depth of the solution of FB 6 in separate test-tubes for the tests you will carry out. (i) Add aqueous sodium hydroxide to FB 6 solution. Add aqueous ammonia to FB 6 solution. Record your observations below. (ii) Carry out a test of your choice to show that sulfate ions are present in FB 6. reagent(s) usedobservation(s)(iii) Give the ionic equation for the reaction in test (ii).[4]UCLES 2013 9701/36/O/N/13<br /> Examiners For Use (b) FB 7, FB 8 and FB 9 are aqueous solutions, each containing one cation and one anion. None of the cations and none of the anions in FB 7, FB 8 and FB 9 are identical. (i) Add a 2 cm magnesium strip to a 2 cm depth of each solution in a clean test-tube. Mix pairs of solutions as shown so that you can complete the table shown below. Use 1 cm depths of solutions in clean test-tubes. Record your observations in the table. FB 7 FB 8 FB 9 add a 2 cm strip of magnesium ribbon FB 7 FB 8 [Keep this mixture for use in test (iii)] (ii) The anion present in FB 7 is the sulfate ion. Identify FB 7, giving evidence from your observations. FB 7 is. evidenceUCLES 2013 9701/36/O/N/13 [Turn over<br /> Examiners For Use 10 (iii) Add a 1 cm depth of aqueous hydrogen peroxide, FB 10, to the mixture of FB 7 and FB 9 that you kept from (i). Then add three drops of starch. Record your observation(s). Identify the coloured chemical produced when hydrogen peroxide was added to the mixture of FB 7 and FB 9 and name the anion present in FB 9. observationschemical producedanion in FB 9(iv) Give the chemical formula of the substance you observed when solutions FB 8 and FB 9 were mixed.[7] [Total: 11]UCLES 2013 9701/36/O/N/13<br />

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