The structure of glycolic acid is shown. [Figure showing the structure of glycolic acid, HO-CH2-COOH]. glycolic acid

1. (a)Complete the table to show what you would observe when an aqueous solution of glycolic acid is added separately to each of the reagents. If a reaction occurs, state the functional group of glycolic acid that is responsible for the reaction. reagent Na2CO3(aq) 2,4-DNPH acidified Cr2O72- observation with glycolic acid does a reaction occur? ✓ /x functional group[4]
2. (b)(i)Two reaction sequences to make glycolic acid are shown. sequence A HCHO HCN and NaCN reaction 1 X CH2(OH)CO2H reaction 2 sequence B CH3CO2H Br2 reaction 3 CH2BrCO2H CH2(OH)CO2H reaction 4 Draw the structure of X.[1]
3. (b)(ii)Name the reagent for reaction 2.[1]
4. (b)(iii)Name the mechanism of reaction 3.[1]
5. (b)(iv)Suggest the essential condition for reaction 3.[1]
6. (b)(v)Reaction 4 occurs via an SN2 mechanism. Complete the diagram for the mechanism for reaction 4. Include all relevant charges, partial charges, curly arrows and lone pairs. [Figure showing a partial SN2 mechanism for Br substitution by OH-][2]
7. (c)(i)Glycolic acid can also be made by reacting glyoxylic acid with NaBH4. [Figure showing reaction of glyoxylic acid + NaBH4 -> glycolic acid] State the role of NaBH4 in this reaction.[1]
8. (c)(ii)Write an equation for this reaction using molecular formulae. Use [H] to represent NaBH4.[2]
9. (d)(i)When glycolic acid is heated in the presence of a sulfuric acid catalyst, a new compound, Y, C4H4O4, is formed. The equation for the reaction is given. 2CH2(OH)CO2H → C4H4O4 + 2H2O glycolic acid Y The infra-red spectrum of Y is shown. [Figure X.X: IR spectrum of Y] State how this spectrum differs from an infra-red spectrum of glycolic acid. Explain your answer with particular reference to the peaks within the range 1500–4000 cm-1.[2]
10. (d)(ii)Suggest a structure for Y.[2]

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