For each of the following changes at equilibrium, indicate whether the equilibrium shifts...

For each of the following changes at equilibrium, indicate whether the equilibrium shifts in the direction of products, reactants, or does not change:

C2H4(g) + Cl2(g) ⇄ C2H4Cl2(g) + heat

a. raise the temperature of the reaction

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b. decrease the volume of the reaction container

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c. add a catalyst

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d. add more Cl2(g)