OCR A Specimen Paper 3 Q5

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5 This question is about organic acids. (a) Lactic acid, shown below, has two functional groups. 12 reaction with bases: . Lactic acid reacts with bases and with many metals.An aqueous solution containing 1.125 g of lactic acid is reacted with an excess of magnesium producing hydrogen gas.The excess magnesium is removed. The water is evaporated, leaving a white solid, A. (i) Name the type of reaction of lactic acid with bases and with metals. Specimen reaction with metals:(ii) Calculate the volume of H2(g) produced, measured at room temperature and pressure. [1] [2] [1] (iii) What is the empirical formula of the white solid A? volume of H2 =OCR 2014H432/03<br /> (iv) Predict two reactions of lactic acid, each involving a different functional group. 13 Do not include reactions with bases or metals. For each reaction,draw the structures of any organic products formed. state the type of reaction, the reagents and conditions Specimen [4]OCR 2014 H432/03 Turn over<br /> 14 (b) In basic conditions, -amino acids form anions with the general formula, RCH(NH2)COO. These anions can act as bidentate ligands. Copper(II) ions can form a square planar complex with anions of the amino acid glycine (R = H). There are two stereoisomers of this complex, B and C. (i) Draw the skeletal formula of the anion of glycine. [1] [2] (ii) Draw diagrams of stereoisomers B and C. In your structures, show the ligands as skeletal formulae. Specimen (iii) Anion ligands of the amino acid alanine (R = CH3) would be expected to form more than two square planar stereoisomers with copper(II) ions. Explain this statement. .[1]OCR 2014 H432/03<br /> 15 (c) Methanoic acid is added to water. An acidbase equilibrium is set up containing two acidbase pairs. Suggest a mechanism for the forward reaction in this equilibrium. Your mechanism should use displayed formulae and curly arrows, and show all species present at equilibrium. Specimen [2]OCR 2014 H432/03 Turn over<br /> (d) Information about a monobasic organic acid D is shown below. 16D reacts by both electrophilic substitution and electrophilic addition.The molecular formula of D is CxHyO2.The mass spectrum of D has a molecular ion peak at m/z = 148.The 13C NMR spectrum of D contains seven peaks. Determine and draw a possible structure for D. Explain your reasoning from the evidence provided.Specimen[5]OCR 2014 H432/03<br /> BLANK PAGE 17 SpecimenOCR 2014 H432/03 Turn over<br />

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