CIE Jun 2013 v5 Paper 3 Q2

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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. 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. FA 3, FA 4 and FA 5 are aqueous solutions of salts. Read through the tests before starting the practical work. (a) Many cations are identi ed by using aqueous sodium hydroxide and aqueous ammonia in small amounts and then to excess. Carry out the following tests and record all your observations in the table below. Do not discard thenal products in these tests as you will need to use them in part (b). FA 3 observations FA 4 FA 5 test (i) To 1 cm depth of solution in a test-tube, add aqueous sodium hydroxide, until in excess. (do not discard) (ii) To 1 cm depth of solution in a test-tube, add aqueous ammonia, until in excess. (do not discard)UCLES 2013 9701/35/M/J/13 [3] [Turn over<br /> Examiners For Use (b) At least one of the solutions contains a second cation, the ammonium ion, NH4 +. Devise a test to identify which salt or salts contain the ammonium ion. You are to use the products of the reactions in (a) when carrying out your test. (i) Which of the following sets of products will you use in your test? Tick the appropriate box. products with excess aqueous sodium hydroxide products with excess aqueous ammonia (ii) Describe the test and expected observations if NH4 + is present.(iii) Carry out your test and record your observations clearly in the space below. [4]UCLES 2013 9701/35/M/J/13<br /> (c) FA 3, FA 4 and FA 5 each contains a different anion which is sulfate, chloride, or nitrate. Using the Qualitative Analysis Notes on page 11, select reagents to allow you to identify positively which anion is in each salt using the minimum number of tests. Record your reagents and your observations in the table below. Indicate where a test is unnecessary using a dash, . reagent(s) FA 3 FA 4 FA 5 Examiners For Use II III IV II III IV (d) From your observations in (a), (b) and (c), identify as many ions that could be present as possible. FA 3 FA 4 FA 5 [5] cation(s) anion [5] [Total: 17]UCLES 2013 9701/35/M/J/13 [Turn over<br />

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