This question is about compounds containing chlorine.

1. (a)The equation shows the reaction of aqueous methanol with hydrochloric acid. CH3OH(aq) + HCl(aq) → CH3Cl(g) + H2O(l) The progress of this reaction can be followed by taking small samples of the reaction mixture every hour and determining the concentration of hydrochloric acid. Describe a practical method by which the concentration of hydrochloric acid can be determined in a sample.[3]
2. (b)The graph shows how the concentration of hydrochloric acid changes as the reaction proceeds. [Figure: Graph of concentration of HCl in mol/dm³ vs time in hours, with points A, B, C, D marked]
3. (b)(i)Deduce the concentration of hydrochloric acid four hours from the start of the experiment. .............................................................................................................................mol/dm³ [1][1]
4. (b)(ii)At which point on the graph, A, B, C or D, is the rate of reaction fastest? Give a reason for your answer by referring to the graph.[2]
5. (c)Describe and explain, using ideas about collisions between particles, how the rate of a reaction changes when the temperature is decreased. All other conditions stay the same.[3]
6. (d)Describe the effect of hydrochloric acid on Universal Indicator paper.[1]
7. (e)Name a metal chloride that is insoluble in water.[1]
8. (f)Chlorofluorocarbons (CFCs) diffuse into the atmosphere. Describe the effect of CFCs on the atmosphere and explain why this is a problem. effect .......................................................................................................................................... explanation .............................................................................................................................. [2][2]

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