CIE Nov 2015 v1 Paper 4 Q4

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In aqueous solution, 2-chloro-2-methylpropane, (CH3)3CCl, reacts with sodium hydroxide, NaOH. This is a nucleophilic substitution reaction. PMT (CH3)3CCl (aq) + NaOH(aq)(CH3)3COH(aq) + NaCl (aq) (a) Show the mechanism for this reaction. Include all necessary curly arrows, lone pairs and relevant dipoles. The rate of this reaction was investigated using a large excess of sodium hydroxide. (b) The graph below shows the results of the experiment. [3] 0.60 0.50 0.40 [(CH3)3CCl ] / mol dm3 0.30 0.20 0.10 20 40 60 80 time / s 100 120 140 160UCLES 2015 9701/41/O/N/15<br /> PMT The reaction is first order with respect to [(CH3)3CCl ]. This can be confirmed from the graph using half-lives. (i) What is meant by the half-life of a reaction?[1] (ii) Calculate the half-life for this reaction. Show all your working and show clearly any construction lines on the graph. (iii) What would be the effect on the half-life of this reaction if the initial concentration of [(CH3)3CCl ] was doubled?[1] [1] (c) (i) Use the graph in (b) to determine the rate of reaction at 80 s. Show all your working. rate =units[2] The rate equation for this reaction is shown. rate = k [(CH3)3CCl ] (ii) Calculate the value of the rate constant, k, for this reaction and give its units. k =units[1] [Total: 9]UCLES 2015 9701/41/O/N/15 [Turn over<br />

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