an air sample containing molar ratio of 21:79 of o2 and n2 is heated to 2400 degree celcius . if the mole percent of no at euilibrium is 1.8percent .calculate kp for the reaction n2 + o2 equilibrium 2no

Consider the equilibrium,  

                                

Initial conc.                     79    21                              0

At equilibrium              79-x     21-x                          2x

Given:

 2x = 1.8 , x= 0.9

      

Now,

 

In this case Δ n = 2 – 2 = 0

So, K_p = K_c (RT) ° = K_c

 

K_p = 2.1 × 10^-3