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NEET Sample Paper NEET Sample Test Paper-81

  • question_answer
    What will be the value of \[\Delta S\] for conversion of liquid to vapour? Given that enthalpy of vapourisation of liquid diethylether and its boiling point are \[26 kJ mol{{\,}^{-}}^{1}\] and \[35\,C{}^\circ \]respectively.

    A)  \[+\,84.420 J mo{{l}^{-}}^{1}\]        

    B)  \[+\,84.4 J mo{{l}^{-}}^{1}\,{{K}^{-\,1}}\]

    C)  \[+\,8.442 J mo{{l}^{-}}^{1}\]         

    D)  \[-\,84.4 J mo{{l}^{-}}^{1}\,{{K}^{-\,1}}\]

    Correct Answer: B

    Solution :

    Given, \[\Delta {{H}_{vap}}\,\,=\,\,26kJ\,mo{{l}^{-\,1}}\,=\,\,26000\,J\,mo{{l}^{-\,1}}\] \[\operatorname{Tb}=35+273=308K\] \[\Delta {{S}_{vap}}=\frac{\Delta {{H}_{vap}}}{Tb}\] \[=\,\,\frac{26000\,\,J\,mo{{l}^{-\,1}}}{308\,K}\] \[= \,84.42 J{{K}^{-}}^{1}\,mo{{l}^{-}}^{1}\]


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