Question

another way to write the equation c₂h₆(g) ⇌ c₂h₂(g) + 2 h₂(g) δh = +3.2 × 10² kj/mol is select one: a. 2 h₂(g) + c₂h₂(g) + 3.2 × 10² kj ⇌ c₂h₆(g) b. c₂h₆(g) ⇌ c₂h₂(g) + 2 h₂(g) + 3.2 × 10² kj c. c₂h₆(g) - 3.2 × 10² kj ⇌ c₂h₂(g) + 2 h₂(g) d. c₂h₆(g) + 3.2 × 10² kj ⇌ c₂h₂(g) + 2 h₂(g)

Explanation:

Step1: Analyze the chemical - equation and enthalpy

The given equation is $C_2H_6(g)
ightleftharpoons C_2H_2(g)+2H_2(g)$ with $\Delta H = + 3.2\times10^{2}\text{kJ/mol}$. This is an endothermic reaction. The reverse reaction would be $C_2H_2(g)+2H_2(g)
ightleftharpoons C_2H_6(g)$ with $\Delta H=-3.2\times10^{2}\text{kJ/mol}$.

Step2: Check each option

Option a: $2H_2(g)+C_2H_2(g)
ightleftharpoons C_2H_6(g)+3.2\times10^{2}\text{kJ}$ is incorrect as the sign of the energy in the reaction should be negative for the reverse reaction. Option b: $C_2H_6(g)
ightleftharpoons C_2H_2(g)+2H_2(g)+3.2\times10^{2}\text{kJ}$ is incorrect because for an endothermic forward - reaction, the energy is absorbed, not released on the product side. Option c: $C_2H_6(g)-3.2\times10^{2}\text{kJ}
ightleftharpoons C_2H_2(g)+2H_2(g)$ is an incorrect way of writing the energy in the reaction. Option d: $C_2H_6(g)
ightleftharpoons C_2H_2(g)+2H_2(g)+3.2\times10^{2}\text{kJ}$ is incorrect as the energy is written wrongly for an endothermic reaction. The correct way to write the reverse reaction is $C_2H_2(g)+2H_2(g)
ightleftharpoons C_2H_6(g)$ with $\Delta H=-3.2\times10^{2}\text{kJ/mol}$, but among the given options, the correct representation of the original endothermic reaction is $2H_2(g)+C_2H_2(g)
ightleftharpoons C_2H_6(g)+3.2\times10^{2}\text{kJ}$ written in a wrong - sign way for the energy term in the context of the forward reaction. The correct forward reaction representation is $C_2H_6(g)
ightleftharpoons C_2H_2(g)+2H_2(g)$ and $\Delta H = + 3.2\times10^{2}\text{kJ/mol}$ which is equivalent to $C_2H_6(g)
ightleftharpoons C_2H_2(g)+2H_2(g)$ and the energy is absorbed. The closest correct option considering the forward reaction is a.

Answer:

a. $2H_2(g)+C_2H_2(g)
ightleftharpoons C_2H_6(g)+3.2\times10^{2}\text{kJ}$ (Note: The sign of energy in this option is wrong for the forward reaction but it is the closest in terms of reactants and products representation)