CIE Nov 2014 v6 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 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. Marks are not given for chemical equations. 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. Halfll the 250 cm3 beaker with water and heat it until the water is approximately 60 C. Leave to stand. This water will be used as a water bath. Turn off the Bunsen burner when the water is hot. (a) FB 7 and FB 8 are aqueous solutions. One of the elements present in the different ions in FB 7 and FB 8 is the same. Carry out the following tests on FB 7 and FB 8 and complete the table. test observations (i) To a 1 cm depth of FB 7 in a test-tube add a 1 cm depth of aqueous silver nitrate. (ii) To a 1 cm depth of FB 7 in a test-tube add aqueous sodium hydroxide. (iii) (iv) To a 1 cm depth of FB 7 in a test-tube add a 1 cm depth of aqueous sodium hydroxide and then a 1 cm depth of hydrogen peroxide. Leave to stand. this test, the Before starting Bunsen burner must be turned off. To a 2 cm depth of dilute sulfuric acid add a few drops of FB 8 then add a 1 cm depth of ethanol. Leave to stand in the water bath.UCLES 2014 9701/36/O/N/14 [5] [Turn over<br /> PMT (b) What element is present in both FB 7 and FB 8?[1] (c) Solid FB 9 and aqueous solution FB 10 both contain the same cation. (i) Transfer approximately half of the FB 9 into a hard-glass test-tube and heat. observations(ii) Transfer the remaining FB 9 into a boiling tube and carefully add dilute sulfuric acid. observations(iii) To a 1 cm depth of FB 10 in a test-tube, add a piece of magnesium ribbon. Leave to stand. observations(iv) To a 1 cm depth of FB 10 in a test-tube, add an equal depth of concentrated hydrochloric acid (care: this is very corrosive). observations(v) Suggest which cation is present in both FB 9 and FB 10.(vi) What change in the oxidation state of magnesium is occurring during reaction (c)(iii)? Oxidation state change fromto[8] (d) In which part of the Periodic Table are the elements identi ed as being present in FB 7, FB 8, FB 9 and FB 10?[1] [Total: 15]UCLES 2014 9701/36/O/N/14<br />

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