question_answer

The following equilibrium constants are given:                                                                 [AIPMT (S) 2007]

\[{{N}_{2}}+3{{H}_{2}}\,\rightleftharpoons \,2N{{H}_{3}}\,;\,{{K}_{1}}\]

\[{{N}_{2}}+{{O}_{2}}\,\,\rightleftharpoons \,2NO\,;\,{{K}_{2}}\]

\[{{H}_{2}}+1/2\,{{O}_{2}}\,\rightleftharpoons \,{{H}_{2}}O\,;\,{{K}_{3}}\]

The equilibrium constant for the oxidation of \[N{{H}_{3}}\] by oxygen to give NO is:

A)        \[{{K}_{2}}K_{3}^{3}/{{K}_{1}}\]    

B)       \[{{K}_{2}}\,K_{3}^{2}/{{K}_{1}}\]

C)  \[K_{2}^{2}\,{{K}_{3}}/{{K}_{1}}\]

D)                   \[{{K}_{1}}\,{{K}_{2}}/{{K}_{3}}\]

Correct Answer: A

Solution :

The required equation for the oxidation of NH3 by oxygen to give NO is :

For this

For the equation

For the equation

For the equation

For getting the K we must do

substituting the value we get,

so the value of K in terms of K1, K2 and K3 is