Question

A flask containing pure NO₂ was heated to 1250K, a temperature at which the Kpvalue for the decomposition of NO2 is 177.

2 NO₂(g) <---------> 2 NO(g) + O₂(g)

Starting with pure NO₂ , the flask is heated and he partial pressure of O2 at equlibrium is 0.133 am. Calculate the partial pressures of NO and NO₂ at equlibrium and the total pressure in the flask at equlibrium.

P_NO ____________________atm

P_NO2____________________atm

P_total____________________atm

Answer 1

                                 2 NO₂(g) <---------> 2 NO(g) + O₂(g)

Equb pressure             2p                         2p            p

Equilibrium constant , K_p = (p²_NO x p_O2 ) / p²_NO2

Given equilibrium partial pressure of O2 is 0.133 atm

So Equilibrium partial pressure of NO = 2p = 2x0.133 = 0.266 atm

Equilibrium partial pressure of NO2 = 2p = 2x0.133 = 0.266 atm

Total pressure of the reaction mixture = partial pressure of NO2 + partial pressure of NO + partial pressure of O2

= 0.266+0.266+0.133

= 0.665 atm