Cambridge A Level Chemistry 9701 — 2016 May/June Paper 3 · Variant 5

READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Give details of the practical session and laboratory where appropriate, in the boxes provided. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. Use of a Data Booklet is unnecessary. Qualitative Analysis Notes are printed on pages 14 and 15. A copy of the Periodic Table is printed on page 16. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. CHEMISTRY 9701/35 Paper 3 Advanced Practical Skills 1 May/June 2016 2 hours Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level This document consists of 13 printed pages and 3 blank pages. [Turn over IB16 06_9701_35/4RP © UCLES 2016 *8722389789* Session Laboratory For Examiner’s Use 1 2 3 Total

2 9701/35/M/J/16 © UCLES 2016 1 In this experiment you will determine the concentration of a solution of sulfuric acid by titration. FA 1 is sulfuric acid, H2SO4. FA 2 is aqueous sodium hydroxide, containing 4.20 g NaOH dissolved in 1.00 dm3 of water. thymolphthalein indicator (a) Method Dilution of FA 1 • Pipette 10.0 cm3 of FA 1 into the 250 cm3 volumetric flask. • Make the solution up to the mark using distilled water. • Shake the flask thoroughly. • This diluted solution of sulfuric acid is FA 3. Label the flask FA 3. Titration • Fill the burette with FA 2. • Pipette 25.0 cm3 of FA 3 into a conical flask. • Add a few drops of thymolphthalein indicator. • Perform a rough titration and record your burette readings in the space below. The end point is reached when the solution turns a permanent pale blue colour. The rough titre is … cm3. • Carry out as many accurate titrations as you think necessary to obtain consistent results. • Make sure any recorded results show the precision of your practical work. • Record in a suitable form below all of your burette readings and the volume of FA 2 added in each accurate titration. Keep solution FA 1 for use in Questions 2 and 3. [7] I II III IV V VI VII

3 9701/35/M/J/16 © UCLES 2016 [Turn over (b) From your accurate titration results, obtain a suitable value for the volume of FA 2 to be used in your calculations. Show clearly how you obtained this value. 25.0 cm3 of FA 3 required … cm3 of FA 2. [1] (c) Calculations Show your working and appropriate significant figures in the final answer to each step of your calculations. (i) Calculate the number of moles of sodium hydroxide present in the volume of FA 2 calculated in (b). Use the data in the Periodic Table on page 16. moles of NaOH = … mol (ii) Complete the equation for the reaction of sulfuric acid with sodium hydroxide. State symbols are required. … + … → … Na2SO4(aq) + … (iii) Use your answers to (i) and (ii) to calculate the number of moles of sulfuric acid used in each titration. moles of H2SO4 = … mol (iv) Calculate the concentration, in mol dm–3, of sulfuric acid in FA 3. concentration of H2SO4 in FA 3 = … mol dm–3 (v) Calculate the concentration, in mol dm–3, of sulfuric acid in FA 1. concentration of H2SO4 in FA 1 = … mol dm–3 [5] [Total: 13]

4 9701/35/M/J/16 © UCLES 2016 2 In this experiment you will determine the enthalpy change, ∆H, for the decomposition of magnesium carbonate to magnesium oxide. MgCO3(s) → MgO(s) + CO2(g) In order to do this, you will determine the enthalpy changes for the reactions of magnesium carbonate and magnesium oxide with sulfuric acid. Excess of the two magnesium compounds will be used in each experiment. Then you will use Hess’ Law to calculate the enthalpy change for the reaction above. FA 1 is sulfuric acid, H2SO4. FA 4 is magnesium carbonate, MgCO3. FA 5 is magnesium oxide, MgO. (a) Determination of the enthalpy change for the reaction of magnesium carbonate, FA 4, with sulfuric acid, FA 1 (i) Method • Support the plastic cup inside the 250 cm3 beaker. • Use a measuring cylinder to transfer 25 cm3 of FA 1 into the plastic cup. • Measure and record the initial temperature of the FA 1 in the space below. • Add all the FA 4 from the container to the FA 1 in the plastic cup. • Stir constantly until the maximum temperature is reached. • Measure and record the maximum temperature of the contents of the cup. • Rinse out the plastic cup and shake to dry for use in (b). • Calculate and record the temperature rise.

5 9701/35/M/J/16 © UCLES 2016 [Turn over Calculations Show your working and appropriate significant figures in the final answer to each step of your calculations. (ii) Calculate the energy produced during this reaction. [Assume that 4.2 J are needed to raise the temperature of 1.0 cm3 of solution by 1.0 °C.] energy produced = … J (iii) Use your answer to 1(c)(v) to calculate the number of moles of sulfuric acid in 25 cm3 of FA 1. (If you were unable to calculate the concentration of sulfuric acid in FA 1, assume that it is 1.27 mol dm–3. This is not the true value.) moles of H2SO4 = … mol (iv) Calculate the enthalpy change, in kJ mol–1, for the reaction below. MgCO3(s) + H2SO4(aq) → MgSO4(aq) + CO2(g) + H2O(l) enthalpy change = … … kJ mol–1 (sign) (value) [6]

6 9701/35/M/J/16 © UCLES 2016 (b) Determination of the enthalpy change for the reaction of magnesium oxide, FA 5, with sulfuric acid, FA 1 (i) Method • Use the measuring cylinder to transfer approximately 40 cm3 of FA 1 into the 100 cm3 beaker. • Place the beaker on a tripod and gauze. • Heat FA 1 in the beaker until the temperature is between 40 °C and 50 °C. • Support the plastic cup in the 250 cm3 beaker. • Use the measuring cylinder to transfer 25 cm3 of hot FA 1 into the plastic cup. CARE. • Measure and record, in the space below, the initial temperature of FA 1 in the plastic cup. • Immediately, add all the FA 5 from the container to the FA 1 in the plastic cup. • Stir constantly until the maximum temperature is reached. • Measure and record the maximum temperature. • Calculate and record the temperature rise. Calculations Show your working and appropriate significant figures in the final answer to each step of your calculations. (ii) Calculate the energy produced during this reaction. [Assume that 4.2 J are needed to raise the temperature of 1.0 cm3 of solution by 1.0 °C.] energy produced = … J (iii) Use your answer to (a)(iii) to calculate the enthalpy change, in kJ mol–1, for the reaction below. MgO(s) + H2SO4(aq) → MgSO4(aq) + H2O(l) enthalpy change = … … kJ mol–1 (sign) (value) [4]

7 9701/35/M/J/16 © UCLES 2016 [Turn over (c) Use your values for the enthalpy changes calculated in (a)(iv) and (b)(iii) to calculate the enthalpy change for the reaction below. Show clearly how you obtained your answer by drawing a Hess’ Law energy cycle. (If you were unable to calculate the enthalpy changes, assume that the value of the enthalpy change in (a)(iv) is –58.7 kJ mol–1 and the value in (b)(iii) is –140.3 kJ mol–1. Note: these are not the correct values.) MgCO3(s) → MgO(s) + CO2(g) enthalpy change = … … kJ mol–1 (sign) (value) [2] (d) (i) Calculate the maximum percentage error in the temperature rise in (b)(i). percentage error = … % (ii) The magnesium oxide, FA 5, was weighed with a balance measuring to one decimal place. A student suggested that the accuracy of the experiment in (b)(i) would be improved by weighing FA 5 using a balance measuring to two decimal places. State and explain whether or not the student is correct. … … … [2] [Total: 14]

8 9701/35/M/J/16 © UCLES 2016 3 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) FA 6 is a salt containing one cation and one anion from those listed on pages 14 and 15. Transfer a small spatula measure of FA 6 into a hard-glass test-tube. Heat gently at first, then heat strongly until no further change occurs. Record all your observations below. … … … … … … …

9 9701/35/M/J/16 © UCLES 2016 [Turn over (ii) Dissolve the remainder of FA 6 in an approximate depth of 5 cm of distilled water in a boiling tube for use in the following tests. Record your observations in the table below. test observations To a 1 cm depth of the solution of FA 6 in a test-tube, add an equal volume of FA 1, aqueous sulfuric acid. To a 1 cm depth of the solution of FA 6 in a test-tube, add aqueous ammonia. To a 1 cm depth of the solution of FA 6 in a boiling tube, add aqueous sodium hydroxide, then heat the mixture, gently and carefully, then place the boiling tube in a rack and add aluminium foil. (iii) Give the chemical formula of FA 6. … Give the ionic equation for the reaction of FA 6 with cold sodium hydroxide. Include state symbols. … [8]

10 9701/35/M/J/16 © UCLES 2016 (b) (i) FA 7 is a solution containing one cation and one anion from the list on pages 14 and 15. Carry out the following tests and record your observations in the table below. test observations To a 1 cm depth of FA 7 in a test-tube, add aqueous sodium hydroxide. To a 1 cm depth of FA 7 in a test-tube, add aqueous ammonia. To a 1 cm depth of FA 7 in a test-tube, add a few drops of acidified potassium manganate(VII), followed by a few drops of aqueous starch. (ii) Identify FA 7. FA 7 is … (iii) Carry out one further test of your choice to confirm the identity of the anion in FA 7. reagent(s) used … observation(s) … … [5] [Total: 13]

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14 9701/35/M/J/16 © UCLES 2016 Qualitative Analysis Notes Key: [ppt. = precipitate] 1 Reactions of aqueous cations ion reaction with NaOH(aq) NH3(aq) aluminium, Al 3+(aq) white ppt. soluble in excess white ppt. insoluble in excess ammonium, NH4 +(aq) no ppt. ammonia produced on heating – barium, Ba2+(aq) faint white ppt. is nearly always observed unless reagents are pure no ppt. calcium, Ca2+(aq) white ppt. with high [Ca2+(aq)] no ppt. chromium(III), Cr3+(aq) grey-green ppt. soluble in excess giving dark green solution grey-green ppt. insoluble in excess copper(II), Cu2+(aq) pale blue ppt. insoluble in excess blue ppt. soluble in excess giving dark blue solution iron(II), Fe2+(aq) green ppt. turning brown on contact with air insoluble in excess green ppt. turning brown on contact with air insoluble in excess iron(III), Fe3+(aq) red-brown ppt. insoluble in excess red-brown ppt. insoluble in excess magnesium, Mg2+(aq) white ppt. insoluble in excess white ppt. insoluble in excess manganese(II), Mn2+(aq) off-white ppt. rapidly turning brown on contact with air insoluble in excess off-white ppt. rapidly turning brown on contact with air insoluble in excess zinc, Zn2+(aq) white ppt. soluble in excess white ppt. soluble in excess

15 9701/35/M/J/16 © UCLES 2016 2 Reactions of anions ion reaction carbonate, CO3 2– CO2 liberated by dilute acids chloride, Cl –(aq) gives white ppt. with Ag+(aq) (soluble in NH3(aq)) bromide, Br –(aq) gives cream ppt. with Ag+(aq) (partially soluble in NH3(aq)) iodide, I –(aq) gives yellow ppt. with Ag+(aq) (insoluble in NH3(aq)) nitrate, NO3 –(aq) NH3 liberated on heating with OH–(aq) and Al foil nitrite, NO2 –(aq) NH3 liberated on heating with OH–(aq) and Al foil; NO liberated by dilute acids (colourless NO → (pale) brown NO2 in air) sulfate, SO4 2–(aq) gives white ppt. with Ba2+(aq) (insoluble in excess dilute strong acids) sulfite, SO3 2–(aq) gives white ppt. with Ba2+(aq) (soluble in excess dilute strong acids) 3 Tests for gases gas test and test result ammonia, NH3 turns damp red litmus paper blue carbon dioxide, CO2 gives a white ppt. with limewater (ppt. dissolves with excess CO2) chlorine, Cl 2 bleaches damp litmus paper hydrogen, H2 “pops” with a lighted splint oxygen, O2 relights a glowing splint

16 9701/35/M/J/16 © UCLES 2016 To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. Group The Periodic Table of Elements 1 H hydrogen 1.0 2 He helium 4.0 1 2 13 14 15 16 17 18 3 4 5 6 7 8 9 10 11 12 3 Li lithium 6.9 4 Be beryllium 9.0 atomic number atomic symbol Key name relative atomic mass 11 Na sodium 23.0 12 Mg magnesium 24.3 19 K potassium 39.1 20 Ca calcium 40.1 37 Rb rubidium 85.5 38 Sr strontium 87.6 55 Cs caesium 132.9 56 Ba barium 137.3 87 Fr francium – 88 Ra radium – 5 B boron 10.8 13 Al aluminium 27.0 31 Ga gallium 69.7 49 In indium 114.8 81 Tl thallium 204.4 6 C carbon 12.0 14 Si silicon 28.1 32 Ge germanium 72.6 50 Sn tin 118.7 82 Pb lead 207.2 22 Ti titanium 47.9 40 Zr zirconium 91.2 72 Hf hafnium 178.5 104 Rf rutherfordium – 23 V vanadium 50.9 41 Nb niobium 92.9 73 Ta tantalum 180.9 105 Db dubnium – 24 Cr chromium 52.0 42 Mo molybdenum 95.9 74 W tungsten 183.8 106 Sg seaborgium – 25 Mn manganese 54.9 43 Tc technetium – 75 Re rhenium 186.2 107 Bh bohrium – 26 Fe iron 55.8 44 Ru ruthenium 101.1 76 Os osmium 190.2 108 Hs hassium – 27 Co cobalt 58.9 45 Rh rhodium 102.9 77 Ir iridium 192.2 109 Mt meitnerium – 28 Ni nickel 58.7 46 Pd palladium 106.4 78 Pt platinum 195.1 110 Ds darmstadtium – 29 Cu copper 63.5 47 Ag silver 107.9 79 Au gold 197.0 111 Rg roentgenium – 30 Zn zinc 65.4 48 Cd cadmium 112.4 80 Hg mercury 200.6 112 Cn copernicium – 114 Fl flerovium – 116 Lv livermorium – 7 N nitrogen 14.0 15 P phosphorus 31.0 33 As arsenic 74.9 51 Sb antimony 121.8 83 Bi bismuth 209.0 8 O oxygen 16.0 16 S sulfur 32.1 34 Se selenium 79.0 52 Te tellurium 127.6 84 Po polonium – 9 F fluorine 19.0 17 Cl chlorine 35.5 35 Br bromine 79.9 53 I iodine 126.9 85 At astatine – 10 Ne neon 20.2 18 Ar argon 39.9 36 Kr krypton 83.8 54 Xe xenon 131.3 86 Rn radon – 21 Sc scandium 45.0 39 Y yttrium 88.9 57–71 lanthanoids 89–103 actinoids 57 La lanthanum 138.9 89 Ac lanthanoids actinoids actinium – 58 Ce cerium 140.1 90 Th thorium 232.0 59 Pr praseodymium 140.9 91 Pa protactinium 231.0 60 Nd neodymium 144.4 92 U uranium 238.0 61 Pm promethium – 93 Np neptunium – 62 Sm samarium 150.4 94 Pu plutonium – 63 Eu europium 152.0 95 Am americium – 64 Gd gadolinium 157.3 96 Cm curium – 65 Tb terbium 158.9 97 Bk berkelium – 66 Dy dysprosium 162.5 98 Cf californium – 67 Ho holmium 164.9 99 Es einsteinium – 68 Er erbium 167.3 100 Fm fermium – 69 Tm thulium 168.9 101 Md mendelevium – 70 Yb ytterbium 173.1 102 No nobelium – 71 Lu lutetium 175.0 103 Lr lawrencium –

® IGCSE is the registered trademark of Cambridge International Examinations. This document consists of 6 printed pages. © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level CHEMISTRY 9701/35 Paper 3 Advanced Practical Skills 1 May/June 2016 MARK SCHEME Maximum Mark: 40 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the May/June 2016 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

Page 2 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9701 35 © Cambridge International Examinations 2016 Question Indicative material Mark Total 1 (a) I Initial and final readings and titre value given for rough titre and initial and final readings for two (or more) accurate titrations (minimum of 2 x 2 box) 1 II Titre values recorded for accurate titrations and Appropriate headings for the accurate titration table and cm3 units. • initial / start burette reading / volume / value • final / end burette and reading / volume / value • titre or volume / FA2 and used / added unit: / cm3 or (cm3) or in cm3 or cm3 (for each heading) 1 III All accurate burette readings recorded to the nearest 0.05 cm3. Do not award this mark if: • 50(.00) is used as an initial burette reading • more than one final burette reading is 50(.00) • any burette reading is greater than 50(.00) 1 IV There are two (or more) uncorrected, accurate titres within 0.10 cm3 • Do not award this mark if, having performed two titres within 0.1 cm3, a further titration is performed which is more than 0.10 cm3 from the closer of the two initial titres, unless a further titration, within 0.10 cm3 of any other, has also been carried out. • Do not award the mark if any “accurate” burette readings (apart from initial 0 cm3) are given to zero dp. 1 V, VI and VII Examiner rounds any accurate burette to the nearest 0.05 cm3, checks subtractions and then select the ‘best’ titres using the hierarchy: • two (or more) accurate identical titres, then • two (or more) accurate titres within 0.05 cm3, then • two (or more) accurate titres within 0.10 cm3, etc. These best titres should be used to calculate the mean titre, expressed to nearest 0.01 cm3. Accuracy marks are awarded as shown. Award V, VI and VII if δ ⩽ 0.20 cm3 Award V and VI if 0.20 < δ ⩽ 0.40 cm3 Award V only if 0.40 < δ ⩽ 0.60 cm3 3 [7]

Page 3 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9701 35 © Cambridge International Examinations 2016 Question Indicative material Mark Total (b) Candidate must take the average of two (or more) titres that are within a total spread of not more than 0.20 cm3. Working must be shown or ticks must be put next to the two (or more) accurate readings selected. The mean should be quoted to 2 dp, rounded to the nearest 0.01. Two special cases where the mean may not be to 2 dp: • Allow mean expressed to 3 dp only for 0.025 or 0.075 (e.g. 26.325) • Allow mean if expressed to 1 dp if all accurate burette readings were given to 1 dp and the mean is exactly correct. (e.g. 26.0 and 26.2 = 26.1 is allowed) (e.g. 26.0 and 26.1 = 26.1 is incorrect – should be 26.05.) Note: the candidate’s mean will sometimes be marked as correct even if it is different from the mean calculated by the examiner for the purpose of assessing accuracy. 1 [1] (c) (i) Correctly calculates n(NaOH) used = × 4.20 ( ) 40.0 1000 b 1 [5] (ii) (iii) Equation correct 2NaOH(aq) + H2SO4(aq) → Na2SO4(aq) + 2H2O(l) State and symbols must be correct and answer (i) divided by 2 1 (iv) Correct use of 40 × answer (iii) 1 (v) Correct use of 25 × answer (iv) 1 All answers to 3 or 4 significant figures (minimum 3 answers attempted) 1 Question 1 [13]

Page 4 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9701 35 © Cambridge International Examinations 2016 Question Indicative material Mark Total 2 (a) (i) Tables / lists of data in (a) and (b) • Three unambiguous headings • Unit ‘covering’ all temperatures • Four thermometer readings recorded • Two temperature changes recorded 1 Readings and subtraction in (a) and (b) • All four thermometer readings recorded to 0.0 or 0.5 °C • Both temperature changes correctly subtracted 1 Accuracy mark awarded as shown. Examiner checks subtractions and compares the candidate’s temperature rise with the Supervisor’s. The difference is δ. If δ ⩽ 1.0 °C, award one mark If ∆T ⩾ 20.0 °C then award for δ ⩽ 2.0 °C 1 [6] (ii) Correctly calculates energy produced in (a) Energy produced = 25 × 4.2 × temperature change Answer correct to 2 to 4 significant figures. 1 (iii) Correctly calculates n(H2SO4) = 0.025 × 1(c)(v) Answer must be correct to 2, 3 or 4 significant figures. 1 (iv) Correct expression and negative sign Enthalpy change = – × ( ) 1 ( ) 1000 ans ii ans iii Answer must be correct to 2, 3 or 4 significant figures. 1 (b) (i) Accuracy mark awarded as shown. Examiner checks subtractions and compares the candidate’s temperature rise with the supervisor’s. The difference is δ • If δ ⩽ 1.0 °C, award two Q marks • If 1.0 < δ ⩽ 2.0 °C, award one Q mark 2 (ii) Correctly calculates energy produced in (b) • Energy produced = 25 × 4.2 × temp rise • Answer correct and expressed to 2, 3 or 4 significant figures. 1 (iii) Correct expression and negative sign Enthalpy change = × ( )( ) 1 ( )( ) 1000 answer b ii a iii Answer must be correct to 2, 3 or 4 significant figures. 1 [4]

Page 5 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9701 35 © Cambridge International Examinations 2016 Question Indicative material Mark Total (c) Attempt at a Hess’ Law energy cycle • Two correct arrows from the equation • Left arrow labelled with (a)(iv) or numerical value • Right arrow labelled with (b)(iii) or numerical value 1 Correctly calculates enthalpy change Answer = (a)(iv) – (b)(iii) 1 [2] (d) (i) % error = × × 2 0.5 100 ( ) temp rise in b 1 (ii) The student is wrong because MgO is in excess or The student is wrong because H2SO4 is the limiting reagent 1 [2] Question 2 [14]

Page 6 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9701 35 © Cambridge International Examinations 2016 Question Indicative material Mark Total FA 6 is Mg(NO3)2; FA 7 is KI + ZnSO4 (= ZnI2) 3 (a) (i) Observations • (On gentle heating) it melts / dissolves or changes to liquid • Condensation inside tube or steam evolved or fizz / bubbles • (On strong heating) white residue / solid formed • Brown gas / fumes liberated • (Moist blue) litmus turns red • Gas / oxygen relights a glowing spill (or makes it glow brighter) 5 or 6 observations correct = 3 marks 3 or 4 observations correct = 2 marks 1 or 2 observations correct = 1 mark 3 (ii) Observations in first two tests • With H2SO4 – no reaction / no change • With ammonia – white precipitate, insoluble / no change in excess • With cold NaOH - white precipitate and no change / insoluble excess 1 1 Subsequent observations • Ignore observation on heating alone unless a gas is identified or litmus turns blue • When Al is added, gas / NH3 turns litmus blue 1 (iii) Conclusion FA 6 is Mg(NO3)2 1 Mg2+(aq) + 2OH–(aq) → Mg(OH)2(s) 1 [8] (b) (i) Observation with NaOH White precipitate (forms) and soluble in excess (NaOH) 1 Observation with NH3 White precipitate (forms) and soluble in excess (NH3) 1 Both observations required • Brown / orange / red-brown / yellow / yellow-brown (solution) formed and • Goes dark blue/black/blue-black when starch added 1 [5] (ii) Conclusion FA 7 is zinc iodide / ZnI2 1 Correct test and result • Add silver nitrate • Yellow precipitate formed 1 Question 3 [13]