Question

For the gas phase reaction, $C_2{H}_4+H_2\rightleftharpoons C_2{H}_6$, $(\Delta H=-32.7kcal)$ carried out in a vessel, the equilibrium concentration of $C_2{H}_4$ can be increased by :

• A. increasing the temperature
• B. decreasing the pressure
• C. removing some $H_2$
• D. adding some $C_2{H}_6$

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A increasing the temperature
B decreasing the pressure
C removing some $H_2$
D adding some $C_2{H}_6$

A temperature change occurs when the temperature is increased or decreased by the flow of heat. This shifts chemical equilibria toward the products or reactants, which can be determined by studying the reaction and deciding whether it is endothermic or exothermic.

When there is a decrease in pressure, the equilibrium will shift towards the side of the reaction with more moles of gas.

Adding or removing a gaseous reactant or product changes the concentrations. If the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. If more products are added, the system will shift to form more reactants).