Compound V is a liquid. V contains 77.2% carbon, 11.4% hydrogen and 11.4% oxygen by mass. V has a relative molecular mass of 280.

1. (a)Calculate the molecular formula of V. Show your working. molecular formula of V =[3]
2. (b)(i)Describe a chemical test and observation which confirms the presence of a carboxyl functional group.[2]
3. (b)(ii)A 3.196 g sample of Br₂ reacts completely with 2.800g of V. Calculate how many alkene functional groups are present in one molecule of V. Show your working. number of alkene functional groups in V =[1]
4. (c)(i)W, X and Y each contain a common functional group. Name the functional group that is present in all three compounds.[1]
5. (c)(ii)State the formula of the yellow precipitate produced when X is added to alkaline I₂(aq).[1]
6. (c)(iii)W could be one of four structural isomers. • Draw the skeletal formulae for two possible structural isomers of W. • Describe the type of structural isomerism shown.[3]
7. (d)Fig. 5.1 shows the mass spectrum of ketone Z, C₅H₁₀O. [Figure 5.1] Use the information in Fig. 5.1 to suggest the formulae of the fragments with m/e peaks at 29 and 57. Deduce the identity of Z.[3]

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