Ethane can be formed by reacting acetylene with hydrogen. C₂H₂(g) + 2H₂(g) C₂H₆(g) ΔH°_rxn = -311 kJ
Under which reaction conditions would you expect to have the greatest equilibrium yield of ethane?

Question

Ethane can be formed by reacting acetylene with hydrogen. C₂H₂(g) + 2H₂(g)

Ethane can be formed by reacting acetylene with hydrogen. C<sub>2</sub>H<sub>2</sub>(g) + 2H<sub>2</sub>(g) C<sub>2</sub>H<sub>6</sub>(g) ΔH°<sub>rxn</sub> = -311 kJ Under which reaction conditions would you expect to have the greatest equilibrium yield of ethane? A) high temperature, high pressure B) low temperature, high pressure C) high temperature, low pressure D) low temperature, low pressure E) None of these choices are correct.

C₂H₆(g) ΔH°_rxn = -311 kJ
Under which reaction conditions would you expect to have the greatest equilibrium yield of ethane?

Quizplus · Accepted Answer

According to Le Chatelier's Principle, increasing pressure favors the side with fewer moles of gas. In this reaction, the reactants (acetylene and hydrogen) have a total of 3 moles of gas while the product (ethane) has only 1 mole of gas. Therefore, high pressure would favor the yield of ethane. However, since the reaction is exothermic (ΔH°rxn < 0), increasing temperature would also shift the equilibrium to favor the reactants. Therefore, low temperature, high pressure conditions would be the best choice for maximizing the equilibrium yield of ethane.

Ethane Can Be Formed by Reacting Acetylene with Hydrogen