Edexcel Jun 2011 Paper 2 Q17

Answers available below

SECTION B Answer ALL the questions. Write your answers in the spaces provided. 17 This question is about the element chlorine and its compounds. PMT (a) When chlorine is bubbled through water, a solution of chlorine water forms. What is the colour of chlorine water? (1)(b) Chlorine water is added to potassium iodide solution. (i) State the colour of the solution produced. (1)(ii) Write the ionic equation for the reaction, including state symbols. (2) (c) The concentration of chlorine water was found by taking 10.0 cm3 of solution, adding an excess of potassium iodide solution, and titrating with 0.0100 mol dm3 of sodium thiosulfate solution. The experiment was repeated. The following results were obtained. Titration number Final burette reading /cm3 Initial burette reading /cm3 Volume added /cm3 38.60 29.50 9.10 47.60 38.60 9.00 *P38479A0820*<br /> (i) Name a suitable indicator for the titration. State the colour change you would expect to see at the end point. IndicatorColour change fromto(ii) Calculate the mean titre and use this value to calculate the number of moles of sodium thiosulfate used in the titration. Mean titre =cm3 Moles of sodium thiosulfate (iii) Complete the ionic equation for the reaction between iodine and thiosulfate ions. I2(aq) + 2S2O3 2(aq)(cid:3)(cid:111)(cid:3) (iv) Calculate the number of moles of iodine which reacted with the sodium thiosulfate solution. (v) Hence state the number of moles of chlorine present in 10.0 cm3 of the chlorine water. PMT (2) (1) (2) (1) (1) (1) (vi) Calculate the concentration of the chlorine water, in mol dm3. *P38479A0920* Turn over<br /> PMT (d) Potassium burns in chlorine to form potassium chloride. (i) Give the colour of the flame when potassium burns in chlorine. (1)(ii) Write the equation for the reaction between potassium and chlorine. State symbols are not required. (e) Concentrated sulfuric acid is added to potassium chloride in a test tube. Steamy fumes are given off which react with ammonia to give dense white smoke. (i) Name the gas given off in this reaction. (1) (1)(ii) Steamy fumes are observed at the mouth of the test tube. Explain how these fumes are formed. (1)(iii) The steamy fumes react with ammonia to give a dense white smoke. Identify the white smoke by name or formula. (1)(f) 2-chlorobutane can be made from butan-2-ol. (i) Name the chemical you would add to butan-2-ol in the laboratory to make 2-chlorobutane. (1)10 *P38479A01020*<br /> PMT (ii) 2-chlorobutane reacts with alcoholic potassium hydroxide at a high temperature to form a mixture of gaseous alkenes. Draw a fully labelled diagram of the apparatus you would use to prepare and collect this mixture. (3) (Total for Question 17 = 21 marks) *P38479A01120* 11 Turn over<br /> PMT BLANK PAGE 12 *P38479A01220*<br />

Show answer