JEE Main & Advanced Chemistry Thermodynamics / रासायनिक उष्मागतिकी Question Bank Mock Test - Chemical Thermodynamics

  • question_answer
    The enthalpy change states for the following processes are listed below:
    \[C{{l}_{2}}(g)\to 2Cl(g);\] \[242.3kJ\text{ }mo{{l}^{-1}}\]
    \[{{I}_{2}}(g)\to 2I(g);\] \[151.0kJ\text{ }mo{{l}^{-1}}\]
    \[ICl(g)\to I(g)+Cl(g);\] \[211.3kJ\text{ }mo{{l}^{-1}}\]
    \[{{I}_{2}}(s)\to {{I}_{2}}(g);\] \[62.76kJ\text{ }mo{{l}^{-1}}\]
    Given that the standard states for iodine chlorine are \[{{I}_{2}}(s)\] and\[C{{l}_{2}}(g)\], the standard enthalpy o formation for ICl (g) is:

    A) +244.8 kJ \[mo{{l}^{-1}}\]      

    B) -14.6 kJ \[mo{{l}^{-1}}\]

    C)  -16.8kJ \[mo{{l}^{-1}}\]

    D) + 16.8kJ \[mo{{l}^{-1}}\]

    Correct Answer: D

    Solution :

    \[{{I}_{2}}+C{{l}_{2}}\to 2ICl\] \[\Delta H={{e}_{{{I}_{2}}S\to g}}+{{e}_{I-\,I}}+{{e}_{Cl-\,Cl}}-2\times {{e}_{1-\,Cl}}\] \[=62.76+151.0+242.3-2\times 211.3\] \[=33.46kJ\]  for \[2\text{ }mol\text{ }ICl\] \[\therefore \Delta H/mol=\frac{33.46}{2}=16.73kJ\,mo{{l}^{-1}}\]


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