Edexcel Jan 2014 (IAL) Paper 6 Q1 (with explained solutions) |

Skip to content

Edexcel Jan 2014 (IAL) Paper 6 Q1

Answers available below

Answer ALL the questions. Write your answers in the spaces provided. 1 Substance A is a green solid which dissolves in water to form a green solution. Substance A is an ionic compound containing one cation and one anion. (a) Give the formulae of two cations which could be responsible for the green colour in the solid. (2)(b) A student added dilute sodium hydroxide, drop by drop, to an aqueous solution of A. Initially, a green precipitate was formed. The precipitate did not dissolve in excess sodium hydroxide solution. The precipitate darkened on standing to give a brown solid. (i) Write the formula of the cation in substance A. (1)(ii) Write a formula for the green precipitate. (1)(iii) Write a formula for the brown solid. (1)(iv) State the type of reaction involved when the green precipitate turns brown. (1)(c) The student added a few drops of acidified potassium manganate(VII) solution to another sample of a solution of A in a test tube. Describe the colour change that occurs. (1)*P42975RA0216*<br />
(d) The student acidified about 2 cm3 of a solution of A with dilute nitric acid in a test tube and then added a few drops of aqueous silver nitrate solution. A white precipitate was formed. (i) Give the formula of the anion present in A. (1)(ii) The test in (d)(i) is usually followed by the addition of ammonia solution to test the solubility of the precipitate. Explain why this is not a useful procedure in this case. (2)(Total for Question 1 = 10 marks) *P42975RA0316* Turn over<br />

Show answer

Reject Cr2+ Cu(H2O)6 Cu(H2O)4 2+ 2+ 2+ 2+ 3+ Fe2+ / Fe(H2O)6 Ni2+ / Ni(H2O)6 Cr3+ / Cr(H2O)6 Correct Answer Any two from: Allow Cu2+ Ignore names As usual: 1 correct and 1 incorrect scores 1 2 correct and 1 incorrect scores 1 3 correct and 1 incorrect scores 2 Correct Answer Fe2+ / Fe(H2O)6 Ignore names 2+ Reject Mark Mark Acceptable Answers Reject Mark Fe(OH)2/ Fe(H2O)4(OH)2 / Fe(OH)2(H2O)4 Ignore names TE if Ni2+ in (b)(i) then Ni(OH)2/ Ni(H2O)4(OH)2 / Ni(OH)2(H2O)4 score 1. No TE for Cr3+ Question Number 1(a) Question Number 1(b)(i) Question Number 1(b)(ii)<br />
Question Number 1(b)(iii) Acceptable Answers Fe(OH)3/ Fe(H2O)3(OH)3 / Fe(OH)3(H2O)3 Ignore names No TE from (b)(i) ALLOW: Fe2O3 with or without water Question Number 1(b)(iv) Oxidation / redox (reaction) Acceptable Answers Additional information may be given and can be ignored, e.g. green precipitate undergoes oxidation. ALLOW: Oxidation and reduction Reject Mark Reject Mark Just reduction Acceptable Answers Reject Mark Purple to colourless/pale yellow/brown Both required OR Purple (solution) decolourised Allow Pink for purple OR Green to yellow/brown Acceptable Answers Cl(cid:4666)ion(cid:4667) Ignore names: e.g. Chloride (ion) Iron(II) chloride Colourless to purple Green to purple Reject Mark Cl FeCl2 Chlorine ion Question Number 1(c) Question Number 1(d)(i)<br />
Acceptable Answers Reject Mark Question Number 1(d)(ii) (Total for Question 1 = 10 marks) Ammonia reacts with the iron ions to form a precipitate OR A precipitate forms (1) Second mark (A precipitate of) Iron(II) hydroxide/ Iron(III) hydroxide/ Fe(OH)2/ Fe(H2O)4(OH)2/ Fe(OH)3/ Fe(H2O)3(OH)3 (forms) OR Obscures the dissolving of the white precipitate (OWTTE e.g. masks precipitate) (1) ALLOW Precipitate should dissolve but here ammonia is neutralised by nitric acid (1 max)<br />

Question 1 2 3 4

About us | Need Help? | Feedback

Proudly powered by WordPress | Theme: Sydney by aThemes.