S is a secondary alcohol with molecular formula C4H10O. [Reaction scheme diagram] S C4H10O step 1 PBr3 T C4H9Br step 2 U C4H9CN step 3 dilute acid V In step 1, the secondary alcohol S reacts with PBr3 to produce T, which has molecular formula C4H9Br.

1. (a)Draw the displayed formula of S.[1]
2. (b)(i)Give the systematic name of T.[1]
3. (b)(ii)Name the type of reaction that occurs in step 1.[1]
4. (b)(iii)State the reagent(s) and conditions for step 2.[2]
5. (b)(iv)Step 3 involves heating C4HCN with dilute acid to form V. Complete the equation for this reaction. .....C4HCN + ...H+ + .H₂O →[2]
6. (b)(v)An unlabelled sample contains either S, T or U. The sample produces the infrared spectrum shown. [Figure of IR spectrum] Explain how this spectrum confirms that the unknown sample contains U. In your answer identify one relevant absorption in the infrared spectrum and the bond that corresponds to this absorption in the region above 1500cm-1.[1]

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