A mixture of 1.57 mol of N 2 , 1.92 mol of H 2 and 8.13 mol of NH 3 is introduced into a 20 L reaction vessel at 500 K. At this temperature, the equilibrium constant, K c for the reaction N 2 (g) + 3H 2 (g) ⇌ 2NH 3 (g) is 1.7 × 10 2 . Is the reaction mixture at equilibrium? If not, what is the direction of the net reaction?

Question

Philoid · Accepted Answer

Concentration of substance,

[substance] =

Thus, concentrations of given substances are,

[N₂] = 1.57/20 mol L^-1

[H₂] = 1.92/20 mol L^-1

[NH₃] = 8.13/20 mol L^-1

For a chemical change,

aA + bB ⇌ cC + dD

Reaction quotient Q_c for the reaction is,

Q_c =

Where [substance] is concentration of substance at a particular time.

For given reaction

N₂ (g) + 3H₂ (g)⇌2NH₃ (g)

Reaction quotient is,

Q_c = =

Q_c >K_c . Therefore, the reaction proceeds in reverse direction in order to attain equilibrium. (Equilibrium constant is reaction coefficient at equilibrium state)