AQA Jun 2010 Paper 2 Q5

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do not write outside the box sulfuric acid is an important chemical in many industrial and laboratory reactions consider the following three reactions involving sulfuric acid reaction reaction mg oh h so mgso h o the reaction of solid sodium bromide with concentrated sulfuric acid reaction h c ch conc h so h o ch ch oh a give a use for magnesium hydroxide in medicine mark b sulfuric acid behaves as an oxidising agent in reaction b i in terms of electrons state the meaning of the term oxidising agent mark b ii give the formula of the oxidation product that is formed from sodium bromide in reaction mark b iii deduce the half equation for the reduction of h so to so in reaction mark wmp jun chem do not write outside the box c the formation of ethanol in reaction uses concentrated sulfuric acid and proceeds in two stages according to the following equations stage stage h c ch h so ch ch oso oh ch ch oso oh h o ch ch oh h so c i state the overall role of sulfuric acid in reaction mark c ii outline a mechanism for stage of this reaction c iii state the class of alcohols to which ethanol belongs mark c iv draw the displayed formula of the carboxylic acid formed when ethanol is oxidised by an excess of acidified potassium dichromate vi solution marks mark turn over wmp jun chem

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