NEET AIPMT SOLVED PAPER SCREENING 2010

  • question_answer
      For the reaction, \[{{N}_{2}}{{O}_{5}}(g)\xrightarrow[{}]{{}}2N{{O}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\]the value of rate of disappearance of \[{{\text{N}}_{\text{2}}}{{\text{O}}_{\text{5}}}\] is given as \[6.25\times {{10}^{-3}}\]\[\text{mol}\,{{\text{L}}^{\text{-1}}}{{\text{s}}^{\text{-1}}}\]. The rate of formation of NO 3 and 0; is given respectively as

    A) \[6.25\times {{10}^{-3}}mol\,{{L}^{-1}}{{s}^{-1}}\]and \[6.25\times {{10}^{-3}}mol\,{{L}^{-1}}{{s}^{-1}}\]

    B) \[1.25\times {{10}^{-2}}mol\,{{L}^{-1}}{{s}^{-1}}\]and \[3.125\times {{10}^{-3}}mol\,{{L}^{-1}}{{s}^{-1}}\]

    C) \[6.25\times {{10}^{-3}}mol\,{{L}^{-1}}{{s}^{-1}}\]and \[3.125\times {{10}^{-3}}mol\,{{L}^{-1}}{{s}^{-1}}\]

    D) \[1.25\times {{10}^{-3}}mol\,{{L}^{-1}}{{s}^{-1}}\]and \[6.25\times {{10}^{-3}}mol\,{{L}^{-1}}{{s}^{-1}}\]

    Correct Answer: B

    Solution :

    Key Idea Rate of disappearance of reactant = rate of appearance of product \[\text{or-}\frac{\text{1}}{\begin{align}   & \text{stoichiometric}\,\text{coefficient} \\  & \text{of}\,\text{reactant} \\ \end{align}}\]\[\frac{d\text{ }\!\![\!\!\text{ reactant}]}{dt}\] \[\text{=}\,\text{+}\frac{\text{1}}{\begin{align}   & \text{stoichiometric} \\  & \text{coefficient}\,\text{of}\,\text{product} \\ \end{align}}\]\[\frac{\text{d }\!\![\!\!\text{ product }\!\!]\!\!\text{ }}{\text{dt}}\] For the reaction, \[{{N}_{2}}{{O}_{5}}(g)\xrightarrow[{}]{{}}2N{{O}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\]                 \[\frac{-d[{{N}_{2}}{{O}_{5}}]}{dt}=+\frac{1}{2}\frac{d[N{{O}_{2}}]}{dt}\]                 \[=+\frac{2d[{{O}_{2}}]}{dt}\] \[\therefore \]  \[\frac{d[N{{O}_{2}}]}{dt}=-2\frac{d[{{N}_{2}}{{O}_{5}}]}{dt}\]                 \[\text{=}\,\text{2 }\!\!\times\!\!\text{ }\,\text{6}\text{.25 }\!\!\times\!\!\text{ 1}{{\text{0}}^{-3}}\text{mol}\,{{\text{L}}^{-1}}{{\text{s}}^{-1}}\]                 \[\text{=}\,12.\text{5 }\!\!\times\!\!\text{ 1}{{\text{0}}^{-3}}\text{mol}\,{{\text{L}}^{-1}}{{\text{s}}^{-1}}\]                 \[\text{=}\,1.\text{25 }\!\!\times\!\!\text{ 1}{{\text{0}}^{-2}}\text{mol}\,{{\text{L}}^{-1}}{{\text{s}}^{-1}}\]                 \[\frac{d[{{O}_{2}}]}{dt}=-\frac{d[{{N}_{2}}{{O}_{5}}]}{dt}\times \frac{1}{2}\]                 \[=\frac{6.25\times {{10}^{-3}}mol\,{{L}^{-1}}\,{{s}^{-1}}}{2}\]                 \[=3.125\times {{10}^{-3}}mol\,{{L}^{-1}}\,{{s}^{-1}}\]


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