# The partial pressure of CH3OH (g), CO(g)  and H2(g) in equilibrium mixture for the reaction CO(g) + 2H2(g) → CH3OH(g) are 2.0 , 1.0 , and 0.1 atm respectively at 427°C. The value of Kp for decomposition of CH3OH to CO and H2 is

Q: The partial pressure of CH3OH (g), CO(g)  and H2(g) in equilibrium mixture for the reaction CO(g) + 2H2(g) $\rightleftharpoons$ CH3OH(g) are 2.0 , 1.0 , and 0.1 atm respectively at 427°C. The value of Kp for decomposition of CH3OH to CO and H2 is

(A) 102 atm

(B) 2 × 102 atm–1

(C) 50 atm2

(D) 5 × 10–3 atm2

Sol: $\large K_p = \frac{P_{CH_3OH}}{P_{H_2}^2 \times P_{CO}}$

$\large K_p = \frac{2}{1 \times (0.1)^2} = 200$

Kp for reverse reaction will be

$\large K_p’ = \frac{1}{K_p} = \frac{1}{200}$

= 5 × 10–3 atm2

A sample of air consisting of N2 and O2 was heated to 2500 K until the equilibrium N2(g) + O2(g) $\rightleftharpoons$ 2 NO(g) was established with an equilibrium constant Kc = 2.1 × 10–3 . At equilibrium, the mole of NO was 1.8. Estimate the initial composition of air in mole fraction of N2 and O2.

Ans: (D)