JEE Main & Advanced JEE Main Paper (Held On 19 May 2012)

  • question_answer
    The value of\[{{K}_{p}}\]for the equilibrium reaction\[{{N}_{2}}{{O}_{4}}(g)2N{{O}_{2}}(g)\]is 2. The percentage dissociation of \[{{N}_{2}}{{O}_{4}}(g)\]at a pressure of 0.5 atm is     JEE Main  Online Paper (Held On 19  May  2012)

    A) 25                          

    B)                        88

    C)                        50                          

    D)                        71

    Correct Answer: D

    Solution :

                    \[{{N}_{2}}{{O}_{4}}(g)2N{{O}_{2}}(g)\] Initial moles                   1                 0 Moles at equil.             \[(1-\alpha )\]         \[2\alpha \] (\[\alpha =\] degree of dissociation) Total number of moles at equil. \[=1(1-\alpha )+2\alpha \] \[=(1+\alpha )\] \[p{{N}_{2}}{{O}_{4}}=\frac{(1-\alpha )}{a(1+\alpha )}\times P\] \[{{p}_{N{{O}_{2}}}}=\frac{2\alpha )}{a(1+\alpha )}\times P\] \[{{K}_{P}}=\frac{{{({{p}_{N{{O}_{2}}}})}^{2}}}{{{P}_{{{N}_{2}}{{O}_{4}}}}}=\frac{{{\left( \frac{2\alpha }{(1+\alpha )}\times P \right)}^{2}}}{\left( \frac{1-\alpha }{1+\alpha } \right)\times P}=\frac{4{{\alpha }^{2}}P}{1-{{\alpha }^{2}}}\] Given, \[{{K}_{P}}=2,P=0.5\,atm\] \[\therefore \]\[{{K}_{P}}=\frac{4{{\alpha }^{2}}P}{1-{{\alpha }^{2}}}\] \[=\frac{4{{\alpha }^{2}}\times 0.5}{1-{{\alpha }^{2}}}\] \[\alpha =0.707\approx 0.71\] \[\therefore \]Percentage dissociation\[=0.71\times 100=71\]


You need to login to perform this action.
You will be redirected in 3 sec spinner