Question

A 1M solution of SbCl, in an organic solvent shows no noticeable reactivity at room temperature. The sample is heated to 200°C, and the following equilibrium reaction is found to occur:

SbCl₂ ⇌ SbCl₃ + Cl₂

The value of Keq at 200°C was measured to be 10^-⁶. The reaction was then heated to 350°C, and the equilibrium concentration of Cl₂ was found to be 0.1 M. Which of the following best approximated the value of Keq at 350°C?

A) 1.5
B) 1.0
C) 0.1
D) 0.01
E) 0.001

Answer 1

The value of Keq at 350°C can be determined using Le Chatelier's principle, which states that increasing the temperature of an exothermic reaction shifts the equilibrium position to the left. Since the concentration of Cl2 decreases at higher temperatures while Keq remains constant, the value of Keq at 350°C would be smaller than 10^-6, but larger than 10^-7. Option D) 0.01 best approximates this value.

Step-by-step explanation:

Given that the equilibrium constant at 200°C, Keq, is 10^-6 and the equilibrium concentration of Cl2 at 350°C is 0.1 M, we can determine the approximate value of Keq at 350°C by making use of Le Chatelier's principle.

According to Le Chatelier's principle, increasing the temperature of an exothermic reaction (like the one given) will shift the equilibrium position to the left. As a result, the concentration of Cl2 will decrease at higher temperatures. Since the concentration of Cl2 decreases while Keq remains the same (since it is a constant), we can conclude that the value of Keq at 350°C will be smaller than 10^-6, but larger than 10^-7.

Based on the answer choices provided, the best approximation for the value of Keq at 350°C would be option D) 0.01.