2. Solved Papers
  3. NEET

NEET AIPMT SOLVED PAPER SCREENING 2007

  • question_answer
                    Consider the following reactions:                                                                                                                             (i) \[{{H}^{+}}(aq)+O{{H}^{-}}(aq)={{H}_{2}}O(l)\]             \[\Delta H=-{{x}_{1}}\,kJ\,mo{{l}^{-1}}\]                 (ii) \[{{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)={{H}_{2}}O(l)\]\[\Delta H=-{{x}_{2}}\,kJ\,mo{{l}^{-1}}\]                              (iii) \[C{{O}_{2}}(g)+{{H}_{2}}(g)=CO(g)+{{H}_{2}}O(l)\]\[-{{x}_{3}}\,kJ\,mo{{l}^{-1}}\]                 (iv) \[{{C}_{2}}{{H}_{2}}(g)+\frac{5}{2}{{O}_{2}}(g)=2C{{O}_{2}}(g)+{{H}_{2}}O(l)\]\[+{{x}_{4}}\,kJ\,mo{{l}^{-1}}\]                 Enthalpy of formation of \[{{H}_{2}}O(l)\] is:                      

    A)                 \[-{{x}_{2}}\,kJ\,mo{{l}^{-1}}\]

    B)                 \[+{{x}_{3}}\,kJ\,mo{{l}^{-1}}\] 

    C)                 \[-{{x}_{4}}\,kJ\,mo{{l}^{-1}}\]

    D)                 \[-{{x}_{1}}\,kJ\,mo{{l}^{-1}}\]  

    Correct Answer: A

    Solution :

                    Enthalpy of formation: The amount of heat evolved or absorbed during the formation of 1 mole of a compound from its constituent elements is known as heat of formation. So, the correct answer is:                   \[{{H}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\to {{H}_{2}}O(l),\,\Delta H=-{{x}_{2}}\,kJ\,mo{{l}^{-1}}\]


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