2. Sample Papers
  3. NEET

NEET Sample Paper NEET Sample Test Paper-17

  • question_answer
    Given, \[N{{H}_{3}}(g)+3C{{l}_{2}}(g)\]
    \[NC{{l}_{3}}(g)+3HCl(g);-\Delta {{H}_{1}}\]                              (1)
    \[{{N}_{2}}(g)+3{{H}_{2}}(g)2N{{H}_{3}}(g);-\Delta {{H}_{2}}\]     (2)
    \[{{H}_{2}}(g)+C{{l}_{2}}(g)\rightleftharpoons 2HCl(g);\Delta {{H }_{3}}\] (3)
    The heat formation of \[NC{{l}_{3}}\,(g)\]in terms of \[\Delta {{H}_{1}},\,\Delta {{H}_{2}}\]and \[\Delta {{H}_{3}}\]is

    A)  \[\Delta {{H}_{f}}=\Delta {{H}_{1}}+\frac{\Delta {{H}_{2}}}{2}-\frac{3}{2}\Delta {{H}_{3}}\]

    B) \[\Delta {{H}_{f}}=-\Delta {{H}_{1}}+\frac{\Delta {{H}_{2}}}{2}-\frac{3}{2}\Delta {{H}_{3}}\]

    C) \[\Delta {{H}_{f}}=\Delta {{H}_{1}}-\frac{\Delta {{H}_{2}}}{2}-\frac{3}{2}\Delta {{H}_{3}}\]

    D)       None of the above

    Correct Answer: B

    Solution :

    To get\[\frac{1}{2}{{N}_{2}}+\frac{3}{2}C{{l}_{2}}\to NC{{l}_{3}};\,\Delta {{\Eta }_{f}}\] Multiply equation 2 by \[\frac{1}{2},\] equation 3 by \[\frac{3}{2}\] and subtract from the equation 1 and \[\Delta {{H}_{f}}=\Delta {{H}_{1}}-\left( -\frac{\Delta {{H}_{2}}}{2}+\frac{3}{2}\Delta {{\Eta }_{3}} \right)\] \[=-\Delta {{H}_{1}}+\frac{\Delta {{\Eta }_{2}}}{2}-\frac{3}{2}\Delta {{\Eta }_{3}}\] Hence, the correct option is (b).


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