CIE Mar 2016 v2 Paper 4 Q5

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Some reactions of chromium ions are shown below. 10 [Cr(H2O)6]2+(aq) reaction 1 metal + H2SO4 [Cr(H2O)6]3+(aq) reaction 2 Cr2O7 2(aq) PMT H3O+(aq) reaction 3 OH(aq) CrO4 2(aq) (a) (i) Use the Data Booklet to suggest a suitable metal to carry out reaction 1.[1] (ii) Use E o values to explain your answer to (i) by calculating the[2] (b) A student suggested that reaction 2 could be carried out using acidified hydrogen peroxide solution. Use the Data Booklet to show whether or not this reaction is feasible.[2] (c) Explain using oxidation numbers whether or not reaction 3 is a redox reaction.[2]UCLES 2016 9701/42/F/M/16<br /> 11 (d) The student used an acidified solution of Cr2O7 chromium metal. 2(aq) to electroplate a steel box with Calculate how long it would take for a current of 0.125 A to deposit 0.0312 g of chromium metal. PMT time =[3] [Total: 10]UCLES 2016 9701/42/F/M/16 [Turn over<br />

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