Hexane, C6H14, is a colourless liquid. Two test-tubes contain equal amounts of hexane. 1 cm³ of bromine, Br2(aq), is added to both test-tubes. One test-tube is kept in the dark and the other is exposed to sunlight. The table describes the appearance of each test-tube after one hour. test-tube conditions | observations ---|--- in the dark | no change, mixture remains orange in sunlight | colour of mixture fades to pale yellow

1. (a)The test-tube in the dark is kept cool and is not exposed to ultraviolet light. Explain the observations for the test-tube kept in the dark.[2]
2. (b)In sunlight, bromine reacts with hexane by a mechanism which occurs via a series of steps.
3. (b)(i)State the name of the mechanism of the reaction that occurs.[1]
4. (b)(ii)Give an equation which shows a propagation step in this reaction in which hexane produces •C6H13.[1]
5. (b)(iii)Give an equation which shows a propagation step in this reaction that produces 1-bromohexane.[1]
6. (b)(iv)Give an equation which shows a termination step in this reaction that produces 1-bromohexane.[1]
7. (c)A and B are different straight chain alkenes with molecular formula, C6H12. A does not show stereoisomerism. A reacts with potassium manganate(VII) to form hexane-1,2-diol.
8. (c)(i)Draw the structural formula of A.[1]
9. (c)(ii)State the conditions needed for this reaction of A.[2]
10. (d)B reacts with hydrogen gas in the presence of a platinum catalyst to produce hexane.
11. (d)(i)Name the type of reaction occurring.[1]
12. (d)(ii)In terms of σ and π bonds, describe any similarities and differences in the type of carbon-carbon bonds in B and the type of carbon-carbon bonds in hexane.[2]