Set 6 Chemistry [Paper] 2

1 SECTION A (60 Marks) Answer only three questions from this section . 1.(a) Distinguish between order of reaction and activation energy. (02 marks) b) The table below shows the concentration of iodine varying wi th time during the acid catalyzed iodination of propanone . CH3COCH3(aq) + I2(aq) CH3COCH2I(aq) + HI(aq)H+ Time (mins) 0 2 4 6 8 10 12 [I2](mol/dm3) 0.210 0.190 0.166 0.150 0.134 0.110 0.090 (i) Plot a graph of iodine against time and use it to determine: (03½ marks) (ii) Units . (01½ marks) (iii)The order of reaction. (02 mar ks) c) Describe an experiment to show the results in (b) can be determine. (06 marks) d) Ethanol decomposes thermally to form methane and carbon monoxide according the following equation . Standard enthalpy of formation are ∆H fθ[CH 3CHO] = -166kJ/mol. ∆Hfθ[CH 4] = -75kJ/mol & ∆H fθ[CO] = -110kJ/mol The activation energy,Ea = +190kJ/mol Draw the reaction profile for the reaction indicating the values of Ea and Hθreaction . (05 marks) 2. An organic compound, P C 6H12O2 has the following properties .  It forms a yellow precipitate with both Brady’s reagent and iodine solution in presence of sodium hydroxide solution.  It burns with yellow non-sooty flame.  It forms a cloudy solution immediately when treated with concentrated hydrochloric acid in presence of anhydrous zinc chloride. a) Write structural formula and IUPAC name of organic compound, P. (02 mark s) 2 b) Write equation and suggest a mechanism for the reaction between organic compound, P and: (i) Concentrated hydrochloric acid in presence of anhydrous zinc chloride. (03½ marks) (ii) Hot concentrated orthophosphoric acid at 160 ᵒC. (04½ marks) (iii)Potassium cyanide in the presence of dilute sulphuric acid at the temperature less than 20 ᵒC. (03 marks) (iv) Brady’s reagent. (05 marks) c) Using …