For the equilibrium N 2 O 4 (g) 2NO 2 (g), the total pressure at equilibrium is P and the degree of dissociation of N 2 O 4 is alpha. Which expression correctly gives Kp in terms of alpha and P?

Kp = 2 alpha P / (1 - alpha 2 )

For the equilibrium N 2 O 4 (g) 2NO 2…

Answer: Kp = 4 alpha 2 P / (1 - alpha 2 ).

A Kp = 4 alpha2 P / (1 - alpha2)
B Kp = 2 alpha P / (1 - alpha2)
C Kp = alpha2 P / (1 - alpha)
D Kp = 4 alpha P2 / (1 + alpha)

Correct answer: A. Kp = 4 alpha2 P / (1 - alpha2)

Explanation: For N2O4 <=> 2NO2 with initial 1 mole and degree of dissociation alpha, total moles become (1+alpha), and Kp works out to 4 alpha2 P / (1 - alpha2) after substituting mole fractions and total pressure.

As the reaction proceeds, reactant concentration falls and product concentration rises until both level off at equilibrium.

Concept context

When forward and reverse reaction rates are equal, equilibrium is reached. Learn about Kc, Kp, Le Chatelier's principle, and acid-base equilibria, including pH, buffer solutions, and solubility product.

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For the equilibrium N<sub>2</sub>O<sub>4</sub>(g) <=> 2NO<sub>2</sub>(g), the total pressure at equilibrium is P and the degree of dissociation of N<sub>2</sub>O<sub>4</sub> is alpha. Which expression correctly gives Kp in terms of alpha and P?

Concept context

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