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JEE Main & Advanced Sample Paper JEE Main Sample Paper-23

  • question_answer
    The first of ionisation potential for Li is \[5.41\] eV and electron affinity of \[C\,l\] is \[3.61\] eV. Enthalpy of following reaction in kJ/mole is\[L{{i}_{(g)}}+C\,{{l}_{(g)}}\xrightarrow{{}}L{{i}_{(g)}}+C{{\ell }^{-}}_{(g)}(1\,eV\]\[=1.6\times {{10}^{-22}}kJ)\]

    A)  \[160.3\]                                  

    B)  \[173.4\]

    C)  \[868.3\]                                  

    D)  \[672.5\]

    Correct Answer: B

    Solution :

    \[L{{i}_{(g)}}\,\xrightarrow{\,}\,Li_{(g)}^{+}\,+{{e}^{-}}\] \[\Delta {{H}_{1}}=5.41\,\times 1.6\times {{10}^{-22}}kJ/mole\] \[=5.41\,\times 1.6\,\times {{10}^{-22}}\times 6.02\,\times {{10}^{23}}kJ/mole\] \[C{{\ell }_{(g)}}\,+{{e}^{-}}\xrightarrow{\,}\,C{{\ell }^{-}}_{(g)}\] \[\Delta {{H}_{2}}=-3.61\,\times 1.6\times {{10}^{-22}}\,kJ/mole\] \[=-3.61\,\times 1.6\,\times {{10}^{-22}}\,\times 6.02\,\times {{10}^{23}}\,kJ/mole\] on adding \[L{{i}_{(g)}}+C{{l}_{(g)}}\xrightarrow{\,}\,Li_{(g)}^{+}+C{{\ell }^{-}}_{(g)}\] \[=\Delta {{H}_{2}}=\Delta {{H}_{1}}+\Delta {{H}_{2}}=173.4\,\,kJ/mole\]


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