Question

For the reaction Halg) + 12/8) = 2HI(g), K = 50.2 at 445°C. If

[H2] - [62] - [HI] = 1.75 x 10 Mat 445°C, which of the
following is true based on the above?
Qc equilibrium
Qc - Kc, the reaction is currently at equilibrium
Qc > Kc, the reaction proceeds from left to right to reach
equilibrium
QC > Ke the reaction proceeds from right to left to reach
equilibrium

Answer 1

C) Qc < Kc, the reaction proceeds from left to right to reach equilibrium

Further explanation

Given

K = 50.2 at 445°C

[H2] = [I2] = [HI] = 1.75 × 10⁻³ M At 445ºC

Reaction

H2(g) + I2(g) ⇔2HI(g)

Required

Qc

Solution

Qc for the reaction

`\tt Qc=([HI]^2)/([H_2][I_2])\\\\Qc=((1.75.10^(-3))^2)/(1.75.10^(-3)* 1.7* 10^(-3))=1`

Qc < Kc ⇒ reaction from left(reactants) to right (products) (the reaction will shift on the right) until it reaches equilibrium (Qc = Kc)