1. Carbonyl chloride is made by the reversible reaction given below.

CO(g) + Cl₂(g) $\rightleftharpoons$ COCl₂(g)

The forward reaction is exothermic. The reaction is catalysed by carbon within a temperature range of 50 to 150 °C.

i) Predict the effect on the yield of carbonyl chloride of increasing the pressure. Explain your answer.

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ii) If the temperature is allowed to increase to above 200 °C, very little carbonyl chloride is formed. Explain why.

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iii) Explain why a catalyst is used. 

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