OCR A Jun 2009 Paper 2 Q6

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6 A student carried out an investigation to compare the rates of hydrolysis of 1-iodopropane and 1-bromopropane. The student heated hot aqueous sodium hydroxide with each halogenoalkane and found that 1-iodopropane was hydrolysed faster. 12 The equation for the reaction with 1-iodopropane is shown below. CH3CH2CH2OH + I(a) (i) Outline the mechanism for this hydrolysis of 1-iodopropane. CH3CH2CH2I + OH Show curly arrows and relevant dipoles. [3] (ii) State the name of this type of mechanism.[1] (b) Explain why 1-iodopropane is hydrolysed faster than 1-bromopropane.[2] (c) Chlorofluoroalkanes, CFCs, were developed from fluoroalkanes and were used in aerosols and as refrigerants. Under the Montreal Protocol, CFCs are now largely banned because of their ozone-depleting properties. CFCs have now been replaced in many applications. Suggest two reasons why there is still concern about ozone depletion.[2]OCR 2009<br />
 (d) Fluoroalkenes are used to make polymers. For example, PVF, (CH2CHF)n, is used to make non-flammable interiors of aircraft. (i) Draw two repeat units of the polymer PVF showing all bonds. 13 (ii) Draw the structure of the monomer of PVF. [1] [1] (e) Once polymers have been used, they become waste. Outline two ways that waste polymers are processed usefully, rather than just dumped in landfill sites.[2] [Total: 12]OCR 2009 Turn over<br />

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