Solved papers for NEET Chemistry Thermodynamics / रासायनिक उष्मागतिकी NEET PYQ-Thermodynamics

done NEET PYQ-Thermodynamics Total Questions - 81

• question_answer1) Identify the correct statement regarding entropy:                                                                   [AIPMT 1998]
  A)
   At absolute zero temperature, entropy of a perfectly crystalline substance is taken to be zero
  done clear
  B)
        At absolute zero of temperature the entropy of a perfectly crystalline substance is +ve
  done clear
  C)
        At absolute zero of temperature the entropy of all crystalline substance is to be zero
  done clear
  D)
        At \[0{}^\circ C,\] the entropy of a perfectly crystalline substance is taken to be zero
  done clear
  View Answer play_arrow

• question_answer2) One mole of an ideal gas at 300 K is expanded isothermally from an initial volume of 1 L to 10 L.  The \[\Delta E\] for this process is                                                                               [AIPMT 1998]
  A)
   163.7 cal         
  done clear
  B)
        zero                 
  done clear
  C)
   1381.1 cal       
  done clear
  D)
        9 L atm
  done clear
  View Answer play_arrow

• question_answer3) In an endothermic reaction, the value of \[\Delta H\] is:                                                        [AIPMT 1999]
  A)
   zero       
  done clear
  B)
   positive
  done clear
  C)
   negative         
  done clear
  D)
        constant
  done clear
  View Answer play_arrow

• question_answer4) 

  In the reaction

  \[S(s)+\frac{3}{2}{{O}_{2}}(g)\xrightarrow{{}}S{{O}_{3}}(g)+2x\,kcal\]

  and \[S{{O}_{2}}(g)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow{{}}S{{O}_{3}}(s)+y\,kcal\] the heat of formation of \[S{{O}_{2}}\] is:                                                                                                                          [AIPMT 1999]

  A)
         \[(x+y)\]
  done clear
  B)
        \[(x-y)\]
  done clear
  C)
   \[(2x+y)\]
  done clear
  D)
                    \[(2x-y)\]
  done clear
  View Answer play_arrow

• question_answer5) If \[\Delta E\] is the heat of reaction for \[{{C}_{2}}{{H}_{5}}OH(l)+3{{O}_{2}}(g)\xrightarrow{{}}2C{{O}_{2}}(g)+3{{H}_{2}}O(l)\] at constant volume, the \[\Delta H\] (heat of reaction at constant pressure) at constant temperature is:             [AIPMT 2000]
  A)
   \[\Delta H=\Delta E+RT\]          
  done clear
  B)
   \[\Delta H=\Delta E-RT\]
  done clear
  C)
   \[\Delta H=\Delta E-2RT\]
  done clear
  D)
        \[\Delta H=\Delta E+2RT\]
  done clear
  View Answer play_arrow

• question_answer6) The entropy change in the fusion of one mole of a solid melting at \[{{27}^{o}}C\] (Latent heat of fusion,\[2930\text{ }J\text{ }mo{{l}^{-1}}\]) is:                                                                                          [AIPMT 2000]
  A)
   \[9.77\text{ }J\text{ }{{K}^{-1}}mo{{l}^{-1}}\]         
  done clear
  B)
   \[10.73\text{ }J\text{ }{{K}^{-1}}mo{{l}^{-1}}\]
  done clear
  C)
   \[2930\text{ }J\text{ }{{K}^{-1}}mo{{l}^{-1}}\]
  done clear
  D)
                    \[108.5\text{ }J\text{ }{{K}^{-1}}mo{{l}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer7) 

  The factor of \[\Delta G\] values is important in metallurgy. The \[\Delta G\] values for the following reactions at \[{{800}^{o}}C\] are given as:

  \[{{S}_{2}}(s)+2{{O}_{2}}(g)\to 2S{{O}_{2}}(g)\,;\]           \[\Delta G=-544\,kJ\]

  \[2Zn(s)+{{S}_{2}}O\to \,2ZnS(s)\,;\] \[\Delta G=-293kJ\]

  \[2Zn(s)+{{O}_{2}}(g)\to 2ZnO(s);\]   \[\Delta G=-480\,kJ\]

  Then \[\Delta G\] for the reaction

  \[2ZnS(s)+3{{O}_{2}}(g)\xrightarrow{{}}2ZnO(s)+2S{{O}_{2}}(g)\]

  will be:                                                                                                                                     [AIPMT 2000]

  A)
         \[\text{ }357\text{ }kJ\]
  done clear
  B)
        \[-731\text{ }kJ\]
  done clear
  C)
   \[-773\text{ }kJ~\]                   
  done clear
  D)
   \[-229\text{ }kJ\]
  done clear
  View Answer play_arrow

• question_answer8) Change in enthalpy for reaction \[2{{H}_{2}}{{O}_{2}}(l)\xrightarrow{{}}2{{H}_{2}}O(l)+{{O}_{2}}(g)\] If heat of formation of \[{{H}_{2}}{{O}_{2}}(l)\] and \[{{H}_{2}}O(l)\] are \[-188\] and \[-286\text{ }kJ/mol\] respectively:       [AIPMT 2001]
  A)
   \[-196\text{ }k\text{ }J/mol\]
  done clear
  B)
        \[+\text{ }196\text{ }k\text{ }J/mol\]
  done clear
  C)
   \[+948\text{ }k\text{ }J/mol\]
  done clear
  D)
        \[-948\text{ }k\text{ }J/mol\]
  done clear
  View Answer play_arrow

• question_answer9) When 1 mole gas is heated at constant volume, temperature is raised from 298 to 308K. Heat supplied to the gas is 500 J. Then which statement is correct?                                                                                               [AIPMT 2001]
  A)
   \[q=w=500\,J,\,\Delta U=0\]
  done clear
  B)
   \[q=\Delta U=500\,J,\,w=0\]
  done clear
  C)
   \[q=w=500\,J,\,\Delta U=0\]
  done clear
  D)
   \[\Delta U=0,\,\,q=w=-500\,J\]
  done clear
  View Answer play_arrow

• question_answer10) Enthalpy of \[C{{H}_{4}}+\frac{1}{2}{{O}_{2}}\to C{{H}_{3}}OH\] negative. If enthalpy of combustion of \[C{{H}_{4}}\] and \[C{{H}_{3}}OH\] are \[x\] and \[y\] respectively. Then which relation is correct?      [AIPMT 2001]
  A)
   \[x>y\]
  done clear
  B)
                    \[x<y\]
  done clear
  C)
   \[x=y\]
  done clear
  D)
                    \[xy\]
  done clear
  View Answer play_arrow

• question_answer11) 

  \[Pb{{O}_{2}}\xrightarrow{{}}PbO\,\,\Delta {{G}_{298}}<0\]

  \[Sn{{O}_{2}}\xrightarrow{{}}SnO\,\,\Delta {{G}_{298}}>0\]

  Most probable oxidation state of Pb and Sn will be:                                                [AIPMT 2001]

  A)
                                                                \[P{{b}^{4+}},\,S{{n}^{4+}}\]                   
  done clear
  B)
   \[P{{b}^{4+}},\,S{{n}^{2+}}\]
  done clear
  C)
   \[P{{b}^{2+}},\,S{{n}^{2+}}\]
  done clear
  D)
                    \[P{{b}^{2+}},\,S{{n}^{4+}}\]
  done clear
  View Answer play_arrow

• question_answer12) Unit of entropy is:                                                                                                                      [AIPMT 2002]
  A)
   \[J{{K}^{-1}}\,mo{{l}^{-1}}\]                      
  done clear
  B)
   \[J\,mo{{l}^{-1}}\]
  done clear
  C)
   \[{{J}^{-1}}{{K}^{-1}}\,mo{{l}^{-1}}\]                  
  done clear
  D)
   \[JK\,mo{{l}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer13) In a closed insulated container a liquid is stirred with a paddle to increase the temperature, which of the following is true?                                                                                                                                      [AIPMT 2002]
  A)
   \[\Delta E=\Delta W\ne 0,\,q=0\]
  done clear
  B)
   \[\Delta E=W=0,\,q\ne 0\]
  done clear
  C)
   \[\Delta E=0,\,W=q\ne 0\]         
  done clear
  D)
   \[W=0,\,\Delta W=q\ne 0\]
  done clear
  View Answer play_arrow

• question_answer14) 2 mole of ideal gas at \[27{}^\circ C\] temperature is expanded reversibly from 2 L to 20 L. Find entropy change (R = 2 cal/mol K):                                                                                                                    [AIPMT 2002]
  A)
   92.1   
  done clear
  B)
        0      
  done clear
  C)
   4      
  done clear
  D)
        9.2
  done clear
  View Answer play_arrow

• question_answer15) Heat of combustion \[\Delta {{H}^{o}}\] for \[C(s),\,\,{{H}_{2}}(g)\] and\[C{{H}_{4}}(g)\] are -94, -68 and -213 kcal/mol. Then \[\Delta {{H}^{o}}\] for \[C(s)+2{{H}_{2}}(g)\xrightarrow[{}]{{}}C{{H}_{4}}(g)\] is:  [AIPMT 2002]
  A)
         - 17 kcal
  done clear
  B)
        - 111 kcal
  done clear
  C)
        - 170 kcal   
  done clear
  D)
   - 85 kcal
  done clear
  View Answer play_arrow

• question_answer16) The densities of graphite and diamond at 298 K are 2.25 and \[3.31\text{ }g\text{ }c{{m}^{-3}}\], respectively. If the standard free energy difference \[(\Delta {{G}^{o}})\] is equal to \[1895\text{ }J\text{ }mo{{l}^{-1}},\] the pressure at which graphite will be transformed into diamond at 298 K is:                                                         [AIPMT 2003]
  A)
         \[9.92\times {{10}^{6}}\,Pa\]  
  done clear
  B)
   \[9.92\times {{10}^{5}}\,P\]
  done clear
  C)
   \[9.92\times {{10}^{8}}\,Pa\]
  done clear
  D)
        \[9.92\times {{10}^{7}}Pa\]
  done clear
  View Answer play_arrow

• question_answer17) On the basis of the information available from the reaction \[\frac{4}{3}Al+{{O}_{2}}\to \frac{2}{3}\,A{{l}_{2}}{{O}_{3}},\,\Delta G=-827\,kJ\,mo{{l}^{-1}}\] of \[{{O}_{2}},\] the minimum emf required to carry out an electrolysis of \[A{{I}_{2}}{{O}_{3}}\] is \[(F=96500\text{ }C\text{ }mo{{l}^{-1}})\]                                                                                             [AIPMT 2003]
  A)
         6.42 V
  done clear
  B)
        8.56 V 
  done clear
  C)
   2.14 V 
  done clear
  D)
                    4.28 V
  done clear
  View Answer play_arrow

• question_answer18) The molar heat capacity of water at constant pressure, C, is \[75\text{ }J{{K}^{-1}}mo{{l}^{-1}}\]. When 1.0 kJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is:                    [AIPMT 2003]
  A)
   4.8 K              
  done clear
  B)
   6.6 K
  done clear
  C)
   1.2 K              
  done clear
  D)
   2.4 K
  done clear
  View Answer play_arrow

• question_answer19) What is the entropy change (in\[J{{K}^{-1}}mo{{l}^{-1}}\]) when one mole of ice is converted into water at \[0{}^\circ C\]? (The enthalpy change for the conversion of ice to liquid water is \[6.0\text{ }kJ\text{ }mo{{l}^{-1}}\] at \[0{}^\circ C\])                                                                                                                                    [AIPMT 2003]
  A)
   2.198  
  done clear
  B)
        21.98
  done clear
  C)
   20.13 
  done clear
  D)
        2.013
  done clear
  View Answer play_arrow

• question_answer20) For which one of the following equations \[\Delta H_{nreact}^{o}\] equal to \[\Delta H_{f}^{o}\] for the product?                                                                                                                                       [AIPMT 2003]
  A)
   \[Xe(g)+2{{F}_{2}}(g)\xrightarrow[{}]{{}}Xe{{F}_{4}}(g)\]       
  done clear
  B)
   \[2CO(g)+{{O}_{2}}(g)\xrightarrow[{}]{{}}2C{{O}_{2}}(g)\]
  done clear
  C)
        \[{{N}_{2}}(g)+{{O}_{3}}(g)\xrightarrow[{}]{{}}2C{{O}_{2}}(g)\]
  done clear
  D)
                    \[C{{H}_{4}}(g)+2C{{l}_{2}}(g)\xrightarrow[{}]{{}}C{{H}_{2}}C{{l}_{2}}(\ell )+2HCl\,(g)\]
  done clear
  View Answer play_arrow

• question_answer21) 

  Formation of a solution from two components can be considered as:                         [AIPMT 2003]

  (1) pure solvent\[\to \]separated solvent molecules, \[\Delta {{H}_{1}}\]

  (2) pure solute\[\to \]separated solute molecules, \[\Delta {{H}_{2}}\]

  (3) separated solvent and solute molecules \[\to \] solution, \[\Delta {{H}_{3}}\]

  Solution so formed will be ideal if:

  A)
   \[\Delta {{H}_{so\ln }}=\Delta {{H}_{1}}-\Delta {{H}_{2}}-\Delta {{H}_{3}}\]             
  done clear
  B)
   \[\Delta {{H}_{so\ln }}=\Delta {{H}_{3}}-\Delta {{H}_{1}}-\Delta {{H}_{2}}\]
  done clear
  C)
  \[\Delta {{H}_{so\ln }}=\Delta {{H}_{1}}+\Delta {{H}_{2}}+\Delta {{H}_{3}}\]
  done clear
  D)
                    \[\Delta {{H}_{so\ln }}=\Delta {{H}_{1}}+\Delta {{H}_{2}}-\Delta {{H}_{3}}\]
  done clear
  View Answer play_arrow

• question_answer22) 

  For the reaction,

  \[{{C}_{3}}{{H}_{8}}(g)+5{{O}_{2}}(g)\xrightarrow[{}]{{}}3C{{O}_{2}}(g)+4{{H}_{2}}O\,(l)\]

  at constant temperature, \[\Delta H-\Delta E\]is                                                                   [AIPMT 2003]

  A)
         + 3 RT           
  done clear
  B)
   - RT
  done clear
  C)
   + RT              
  done clear
  D)
   - 3 RT
  done clear
  View Answer play_arrow

• question_answer23)  If the bond energies of \[H-H,\,\,Br-Br\] and\[H-Br\] are 433, 192 and 364 kJ \[mo{{l}^{-1}}\] respectively, then \[\Delta {{H}^{0}}\] for the reaction\[{{H}_{2}}(g)+B{{r}_{2}}(g)\xrightarrow[{}]{{}}2HBr(g)\] is:           [AIPMT (S) 2004]
  A)
   \[-261\text{ }kJ\]
  done clear
  B)
                   \[+103\text{ }kJ\]        
  done clear
  C)
   \[+261\text{ }kJ\]        
  done clear
  D)
        \[-103\text{ }kJ\]
  done clear
  View Answer play_arrow

• question_answer24) Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are\[-382.64\,KJ\,mo{{l}^{-1}}\] and \[-145.6\,J{{K}^{-1}}\,mo{{l}^{-1}},\] respectively. Standard Gibbs energy change for the same reaction at 298 K is:                                                                                                                                     [AIPMT (S) 2004]
  A)
   \[-2221.1\,\,kJ\,\,mo{{l}^{-1}}\]
  done clear
  B)
        \[-339.3\,\,kJ\,\,mo{{l}^{-1}}\]
  done clear
  C)
   \[-\,439.3\text{ }kJ\text{ }mo{{l}^{-1}}\]
  done clear
  D)
        \[-523.2\,kJ\,mo{{l}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer25) The maximum number of molecules is present in:                                                    [AIPMT (S) 2004]
  A)
   \[15\,L\] of \[{{H}_{2}}\] gas at STP
  done clear
  B)
        \[5\,L\] of \[{{N}_{2}}\] gas at STP
  done clear
  C)
   0.5 g of \[{{H}_{2}}\] gas
  done clear
  D)
        10 g of \[{{O}_{2}}\]
  done clear
  View Answer play_arrow

• question_answer26) Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is:                                                                                                                                                           [AIPMT (S) 2004]
  A)
   \[\Delta \,{{S}_{\text{system}}}+\Delta {{S}_{\text{surroundings}}}>0\]
  done clear
  B)
   \[\Delta \,{{S}_{\text{system}}}-\Delta {{S}_{\text{surroundings}}}>0\]
  done clear
  C)
   \[\Delta \,{{S}_{\text{system}}}>0\] only
  done clear
  D)
   \[\Delta {{S}_{\text{surroundings}}}>0\] only
  done clear
  View Answer play_arrow

• question_answer27) The work done during the expansion of a gas from a volume of \[4\,d{{m}^{3}}\] to \[6\,d{{m}^{3}}\] against a constant external pressure of 3 atm, is:                                                                                                [AIPMT (S) 2004]
  A)
   \[-\,\,6\,\,J\]      
  done clear
  B)
        \[-\,\,608\,\,J\]
  done clear
  C)
   \[+\text{ }304\text{  }J\]          
  done clear
  D)
        \[-\text{ }304\text{ }J\]
  done clear
  View Answer play_arrow

• question_answer28) A reaction occurs spontaneously if:                                                                                 [AIPMT (S) 2005]
  A)
    \[T\Delta S<\Delta H\] and both \[\Delta H\] and \[\Delta S\] are +ve
  done clear
  B)
   \[T\Delta S>\Delta H\] and both \[\Delta H\] and \[\Delta S\] are +ve
  done clear
  C)
         \[T\Delta S=\Delta H\] and both \[\Delta H\] and \[\Delta S\] are +ve
  done clear
  D)
        \[T\Delta S>\Delta H\] and  \[\Delta H\] is + ve and \[\Delta S\] is -ve
  done clear
  View Answer play_arrow

• question_answer29) Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction? [AIPMT (S) 2005]
  A)
   Exothermic and decreasing disorder
  done clear
  B)
        Endothermic and increasing disorder
  done clear
  C)
        Exothermic and increasing disorder          
  done clear
  D)
        Endothermic and decreasing disorder
  done clear
  View Answer play_arrow

• question_answer30) The absolute enthalpy of neutralisation of the reaction: \[MgO(s)+2HCl\,(aq)\,MgC{{l}_{2}}(aq)\] \[+{{H}_{2}}O\,(l)\] will be:                                                                                             [AIPMT (S) 2005]
  A)
         less than \[-\text{ }57.33\text{ }kJ\text{ }mo{{l}^{-1}}\]
  done clear
  B)
   \[-\text{ }57.33\text{ }kJ\text{ }mo{{l}^{-1}}\]
  done clear
  C)
   greater than \[-\text{ }57.33\text{ }kJ\text{ }mo{{l}^{-1}}\]              
  done clear
  D)
   \[\text{ }57.33\text{ }kJ\text{ }mo{{l}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer31) 

  Equilibrium constants \[{{K}_{1}}\] and \[{{K}_{2}}\] for the following equilibria:

  \[{{N}_{2}}(g)+\frac{1}{2}{{O}_{2}}\,N{{O}_{2}}(g)\,\] and

  \[2N{{O}_{2}}(g)\,2NO(g)+{{O}_{2}}(g)\]

  are related as:                                                                                                            [AIPMT (S) 2005]

  A)
         \[{{K}_{2}}=\frac{1}{{{K}_{1}}}\]                
  done clear
  B)
   \[{{K}_{2}}=K_{1}^{2}\]      
  done clear
  C)
   \[{{K}_{2}}=\frac{{{K}_{1}}}{2}\]                
  done clear
  D)
   \[{{K}_{2}}=\frac{1}{K_{1}^{2}}\]
  done clear
  View Answer play_arrow

• question_answer32) Identify the correct statement for change of Gibbs energy for a system \[(\Delta {{G}_{system}})\] at constant temperature and pressure:                                                                                                                         [AIPMT (S) 2006]
  A)
    If \[\Delta {{G}_{\text{system}}}>0,\] the process is spontaneous
  done clear
  B)
         If \[\Delta {{G}_{\text{system}}}=0,\] the system has attained equilibrium
  done clear
  C)
         If \[\Delta {{G}_{\text{system}}}=0,\] the system is still moving in a particular direction
  done clear
  D)
         If \[\Delta {{G}_{\text{system}}}<0,\] the process is not spontaneous
  done clear
  View Answer play_arrow

• question_answer33) Assume each reaction is carried out in an open container. For which reaction will \[\Delta H=\Delta E\]? [AIPMT (S) 2006]
  A)
   \[{{H}_{2}}(g)+B{{r}_{2}}(g)\,2HBr\,(g)\]
  done clear
  B)
                    \[C\,(s)+2{{H}_{2}}O\,\,(g)\,2{{H}_{2}}\,\,(g)+C{{O}_{2}}\,(g)\]
  done clear
  C)
   \[PC{{l}_{5}}\,\,(g)\,\,~PC{{l}_{3}}\,\,(g)+C{{l}_{2}}\,\,(g)\]
  done clear
  D)
   \[2\,CO\,\,(g)\text{ }+\text{ }{{O}_{2}}\,\,(g)\,\,2C{{O}_{2}}\,(s)\]
  done clear
  View Answer play_arrow

• question_answer34) The enthalpy and entropy change for the reaction: \[B{{r}_{2}}(l)+C{{l}_{2}}(g)\to 2BrCl(g)\] are \[30\,\,kJ\,\,mo{{l}^{-1}}\] and \[105\,\,k{{J}^{-1}}\,\,mo{{l}^{-1}}\] respectively. The temperature at which the reaction will be in equilibrium is:                                                                                                                                     [AIPMT (S) 2006]
  A)
   285.7 K             
  done clear
  B)
   273 K
  done clear
  C)
   450 K    
  done clear
  D)
           300 K
  done clear
  View Answer play_arrow

• question_answer35) 

  For the reaction,

  \[C{{H}_{4}}(g)+2{{O}_{2}}(g)\rightleftharpoons C{{O}_{2}}(g)+2{{H}_{2}}O(\ell )\,,\]\[{{\Delta }_{r}}H=-170.8\,kJ\,mo{{l}^{-1}}\]

  Which of the following statements is not true?                                                                    [AIPMT (S) 2006]

  A)
   At equilibrium, the concentrations of \[C{{O}_{2}}\,(g)\] and \[{{H}_{2}}O\,(l)\] are not equal
  done clear
  B)
               The equilibrium constant for the reaction is given by \[{{K}_{p}}=\frac{[C{{O}_{2}}]}{[C{{H}_{4}}][{{O}_{2}}]}\]
  done clear
  C)
        Addition of \[C{{H}_{4}}\left( g \right)\] or \[{{O}_{2}}(g)\] at equilibrium will cause a shift to the right
  done clear
  D)
        The reaction is exothermic
  done clear
  View Answer play_arrow

• question_answer36) 

  The following equilibrium constants are given:                                                                 [AIPMT (S) 2007]

  \[{{N}_{2}}+3{{H}_{2}}\,\rightleftharpoons \,2N{{H}_{3}}\,;\,{{K}_{1}}\]

  \[{{N}_{2}}+{{O}_{2}}\,\,\rightleftharpoons \,2NO\,;\,{{K}_{2}}\]

  \[{{H}_{2}}+1/2\,{{O}_{2}}\,\rightleftharpoons \,{{H}_{2}}O\,;\,{{K}_{3}}\]

  The equilibrium constant for the oxidation of \[N{{H}_{3}}\] by oxygen to give NO is:

  A)
         \[{{K}_{2}}K_{3}^{3}/{{K}_{1}}\]    
  done clear
  B)
        \[{{K}_{2}}\,K_{3}^{2}/{{K}_{1}}\]
  done clear
  C)
   \[K_{2}^{2}\,{{K}_{3}}/{{K}_{1}}\]
  done clear
  D)
                    \[{{K}_{1}}\,{{K}_{2}}/{{K}_{3}}\]
  done clear
  View Answer play_arrow

• question_answer37) 

  Consider the following reactions:                                                                                       [AIPMT (S) 2007]

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

  Enthalpy of formation of \[{{H}_{2}}O(l)\] is:

  A)
               \[-{{x}_{2}}\,kJ\,mo{{l}^{-1}}\]                     
  done clear
  B)
   \[+{{x}_{3}}\,kJ\,mo{{l}^{-1}}\]
  done clear
  C)
   \[-{{x}_{4}}\,kJ\,mo{{l}^{-1}}\]         
  done clear
  D)
        \[-{{x}_{1}}\,kJ\,mo{{l}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer38) Given that bond energies of \[H-H\] and \[Cl-Cl\]  are \[430\text{ }kJ\text{ }mo{{l}^{-1}}\] and \[240\text{ }kJ\text{ }mo{{l}^{-1}}\] respectively and \[\Delta {{H}_{f}}\] for \[HCl\] is \[-90\text{ }kJ\text{ }mo{{l}^{-1}}\]. Bond enthalpy' of \[HCl\] is:                                                                                                                   [AIPMT (S) 2007]
  A)
   \[290\text{ }kJ\text{ }mo{{l}^{-1}}\]
  done clear
  B)
                    \[380\text{ }kJ\text{ }mo{{l}^{-1}}\]
  done clear
  C)
  \  \[425\text{ }kJ\text{ }mo{{r}^{-1}}\]   
  done clear
  D)
    \[245\text{ }kJ\text{ }mo{{l}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer39) 

  The equilibrium constant of the reaction:                                                                           [AIPMT (S) 2007]

  \[Cu(s)+2A{{g}^{+}}(aq)~C{{u}^{2+}}(aq)+2Ag(s);\]

  \[E{}^\circ =0.46V\] at \[298\text{ }K\] is:

  A)
   \[2.4\times {{10}^{10}}\]                    
  done clear
  B)
   \[2.4\times {{10}^{50}}\]
  done clear
  C)
   \[4.0\times {{10}^{10}}\]                    
  done clear
  D)
   \[4.0\times {{10}^{15}}\]
  done clear
  View Answer play_arrow

• question_answer40) The efficiency of a fuel cell is given by:                                                                                   [AIPMT (S) 2007]
  A)
   \[\frac{\Delta H}{\Delta G}\]     
  done clear
  B)
                   \[\frac{\Delta G}{\Delta S}\]
  done clear
  C)
   \[\frac{\Delta G}{\Delta H}\]     
  done clear
  D)
                    \[\frac{\Delta S}{\Delta G}\]
  done clear
  View Answer play_arrow

• question_answer41) 

  Which of the following are not state functions?                                                                    [AIPMT (S) 2008]

  (I) \[q+W\]                     (II) q

  (III) W                                       (IV) H-TS

  A)
   (I) and (IV)      
  done clear
  B)
   (II), (III) and (IV)
  done clear
  C)
   (I), (II) and (III) 
  done clear
  D)
        (II) and (III)
  done clear
  View Answer play_arrow

• question_answer42) For the gas phase reaction, \[PC{{l}_{5}}_{(g)}PC{{l}_{3}}(g)+C{{l}_{2}}(g)\] which of the following conditions are correct? [AIPMT (S) 2008]
  A)
   \[\Delta H=0\] and \[\Delta S<0\]
  done clear
  B)
   \[\Delta H>0\] and \[\Delta S>0\]
  done clear
  C)
   \[\Delta H>0\] and \[\Delta S<0\]
  done clear
  D)
   \[\Delta H>0\] and \[\Delta S<0\]
  done clear
  View Answer play_arrow

• question_answer43) What volume of .oxygen gas \[({{O}_{2}})\] measured at \[{{0}^{o}}C\] and 1 atm, is needed to bum completely \[1\,L\] of propane gas \[({{C}_{3}}{{H}_{8}})\] measured under the same conditions?               [AIPMT (S) 2008]
  A)
   7 L                 
  done clear
  B)
        6 L                 
  done clear
  C)
   5 L    
  done clear
  D)
        10 L
  done clear
  View Answer play_arrow

• question_answer44) Bond dissociation enthalpy of \[{{H}_{2}},C{{l}_{2}}\] and \[HCl\] are 434, 242 and 431 kJ \[mo{{l}^{-1}}\] respectively. Enthalpy of formation of HCl is                                                                                                                     [AIPMT (S) 2008]
  A)
   \[93\,kJ\,mo{{l}^{-1}}\]          
  done clear
  B)
        \[-245\,kJ\,mo{{l}^{-1}}\]
  done clear
  C)
   \[-93\,kJ\,mo{{l}^{-1}}\]         
  done clear
  D)
        \[245\,kJ\,mo{{l}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer45) 

  The dissociation equilibrium of a gas \[A{{B}_{2}}\] can be represented as                     [AIPMT (S) 2008]

  \[2A{{B}_{2}}(g)2AB(g)+{{B}_{2}}(g)\]

  The degree of dissociation is \['x'\] and is small compared to 1. The expression relating the degree of dissociation \[(x)\] with equilibrium constant \[{{K}_{p}}\] and total pressure p is

  A)
   \[(2{{K}_{p}}/p)\]        
  done clear
  B)
        \[{{(2{{K}_{p}}/p)}^{1/3}}\]
  done clear
  C)
   \[{{(2{{K}_{p}}/p)}^{1/2}}\] 
  done clear
  D)
        \[({{K}_{p}}/p)\]
  done clear
  View Answer play_arrow

• question_answer46) 

  The values of \[{{K}_{{{p}_{1}}}}\] and \[{{K}_{{{p}_{2}}}}\] for the reactions  [AIPMT (S) 2008]

  \[XY+Z\]                                   ...(i)

  and                   \[A2B\]                          ..(ii)

  are in ratio of 9 : 1. If degree of dissociation of X and A be equal, then total pressure at equilibrium (i) and (ii) are in the ratio

  A)
   3 : 1        
  done clear
  B)
   1 : 9                
  done clear
  C)
   36 : 1      
  done clear
  D)
        1 : 1
  done clear
  View Answer play_arrow

• question_answer47) 

  The value of equilibrium constant of the reaction \[HI(g)\frac{1}{2}{{H}_{2}}(g)+\frac{1}{2}{{I}_{2}}\] is 8.0.

  The equilibrium constant of the reaction                                                                          [AIPMT (S) 2008]

  \[{{H}_{2}}(g)+{{I}_{2}}(g)2HI(g)\] will be

  A)
   \[\frac{1}{16}\]            
  done clear
  B)
   \[\frac{1}{64}\]
  done clear
  C)
   16                   
  done clear
  D)
        \[\frac{1}{8}\]
  done clear
  View Answer play_arrow

• question_answer48) 

  From the following bond energies:                                                  [AIPMT (S) 2009]

  \[H-H\] bond energy: 431.37 kJ \[mo{{l}^{-1}}\]

  \[C=O\] bond energy: 606.10 kJ \[mo{{l}^{-1}}\]

  \[C-C\] bond energy: 336.49 kJ \[mo{{l}^{-1}}\]

  \[C-H\] bond energy: 410.50 kJ  \[mo{{l}^{-1}}\]

  Enthalpy for the reaction,

  \[\underset{\begin{smallmatrix}  | \\  H \end{smallmatrix}}{\overset{\begin{smallmatrix}  H \\  | \end{smallmatrix}}{\mathop{C}}}\,=\underset{\begin{smallmatrix}  | \\  H \end{smallmatrix}}{\overset{\begin{smallmatrix}  H \\  | \end{smallmatrix}}{\mathop{C}}}\,+H-\xrightarrow{{}}H-\underset{\begin{smallmatrix}  | \\  H \end{smallmatrix}}{\overset{\begin{smallmatrix}  H \\  | \end{smallmatrix}}{\mathop{C}}}\,-\underset{\begin{smallmatrix}  | \\  H \end{smallmatrix}}{\overset{\begin{smallmatrix}  H \\  | \end{smallmatrix}}{\mathop{C}}}\,-H\] will be

  A)
   \[1523.6\,kJ\,mo{{l}^{-1}}\]
  done clear
  B)
        \[-243.6\,kJ\,mo{{l}^{-1}}\]
  done clear
  C)
   \[-120.0\,kJ\,mo{{l}^{-1}}\]
  done clear
  D)
        \[553.0\,kJ\,mo{{l}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer49) The values of \[\Delta H\] and \[\Delta S\] for the reaction, \[{{C}_{(\text{graphits)}}}+C{{O}_{2}}(g)\xrightarrow[{}]{{}}\,2\,CO\,(g)\] are 170 kJ and \[170\,J{{K}^{-1}},\] respectively. This reaction will be spontaneous at                                                          [AIPMT (S) 2009]
  A)
   710 K              
  done clear
  B)
        910 K  
  done clear
  C)
   1110 K     
  done clear
  D)
    510 K
  done clear
  View Answer play_arrow

• question_answer50) The energy absorbed by each molecule \[({{A}_{2}})\] of a substance is \[4.4\times {{10}^{-19}}\,J\] and bond energy per molecule is \[4.0\times {{10}^{-19}}\,J\]. The kinetic energy of the molecule per atom will be [AIPMT (S) 2009]
  A)
   \[2.0\times {{10}^{-\,20}}\,J\]
  done clear
  B)
   \[2.2\times {{10}^{-\,19}}\,J\]
  done clear
  C)
   \[2.0\times {{10}^{-\,19}}\,J\] 
  done clear
  D)
        \[4.0\times {{10}^{-\,20}}\,J\]
  done clear
  View Answer play_arrow

• question_answer51) For an endothermic reaction, energy of activation is \[{{E}_{a}}\] and enthalpy of reaction is \[\Delta H\] (both of these in kJ/mol). Minimum value of \[{{E}_{a}}\]  will be                                                               [AIPMT (S) 2010]
  A)
   less than \[\Delta H\]   
  done clear
  B)
        equal to \[\Delta H\]
  done clear
  C)
   more than \[\Delta H\] 
  done clear
  D)
        equal to zero
  done clear
  View Answer play_arrow

• question_answer52) Standard entropies of \[{{X}_{2}},{{Y}_{2}}\] and \[X{{Y}_{3}}\] are 60, 40 and \[50\,J\,{{K}^{-1}}\,mo{{l}^{-1}}\] respectively. For the reaction \[\frac{1}{2}{{X}_{2}}+\frac{3}{2}{{Y}_{2}}X{{Y}_{3}};\Delta H=-30kJ,\] to be at equilibrium, the temperature should be                                                                                 [AIPMT (S) 2010]
  A)
   750 K              
  done clear
  B)
        1000 K
  done clear
  C)
   1250 K            
  done clear
  D)
        500 K
  done clear
  View Answer play_arrow

• question_answer53) 

  Match List I (equations) with List II (types of process) and select the correct option.	[AIPMT (M) 2010]
  List I (Equations) List II (Type of process) A. A. \[{{K}_{p}}>Q\] 1 Non-spontaneous B.  \[\Delta {{G}^{o}}<RT\,\,\ln \,Q\] 2 Equilibrium C. C. \[{{K}_{p}}=Q\] 3  Spontaneous and endothermic D. \[T>\frac{\Delta H}{\Delta S}\] 4 Spontaneous

  A)

  1

  2

  3

  4

  done clear
  B)

  3

  4

  2

  1

  done clear
  C)

  4

  1

  2

  3

  done clear
  D)

  2

  1

  4

  3

  done clear
  View Answer play_arrow

• question_answer54) Three moles of an ideal gas expanded spontaneously into vacuum. The work done will be        [AIPMT (M) 2010]
  A)
   infinite   
  done clear
  B)
                    3 J                  
  done clear
  C)
   9 J                  
  done clear
  D)
        zero
  done clear
  View Answer play_arrow

• question_answer55) For vaporisation of water at 1 atm pressure, the values of \[\Delta H\] and \[\Delta S\] are \[40.63\,kJ\,mo{{l}^{-1}}\] and \[108.8\,J{{K}^{-1}}\,mo{{l}^{-1}}\], respectively. The temperature when Gibbs energy change \[(\Delta G)\] for this transformation will be zero, is                                                                        [AIPMT (M) 2010]
  A)
   273.4 K      
  done clear
  B)
   393.4 K           
  done clear
  C)
   373.4 K              
  done clear
  D)
        293.4 K
  done clear
  View Answer play_arrow

• question_answer56)             

  The following two reactions are known                                           [AIPMT (M) 2010]

  \[F{{e}_{2}}{{O}_{3}}(s)+3CO(g)\xrightarrow[{}]{{}}2Fe(s)+3C{{O}_{2}}(g);\]\[\Delta H=-26.8\,kJ\]

  \[FeO(s)+CO(g)\xrightarrow[{}]{{}}Fe(s)+C{{O}_{2}}(g);\]\[\Delta H=-16.5\,kJ\]

  The value of \[\Delta H\] for the following reaction

  \[F{{e}_{2}}{{O}_{3}}(s)+CO(g)\xrightarrow[{}]{{}}2FeO(s)+C{{O}_{2}}(g)\]

  A)
   \[+10.3\,kJ\]          
  done clear
  B)
        \[-\,43.3\,kJ\]
  done clear
  C)
   \[-\,10.3\,kJ\]     
  done clear
  D)
                    \[+\,6.2\,kJ\]
  done clear
  View Answer play_arrow

• question_answer57) If the enthalpy change for the transition of liquid water to steam is \[30\,kJ\,mo{{l}^{-1}}\] at \[{{27}^{o}}C,\] the entropy change for the process would be                                                                                [AIPMT (S) 2011]
  A)
   \[1.0\,\,J\,mo{{l}^{-1}}\,{{K}^{-1}}\]
  done clear
  B)
   \[0.1\,\,J\,mo{{l}^{-1}}\,{{K}^{-1}}\]
  done clear
  C)
   \[100\,J\,mo{{l}^{-1}}\,{{K}^{-1}}\] 
  done clear
  D)
   \[10\,J\,mo{{l}^{-1}}\,{{K}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer58)  Which of the following is correct option for   free expansion of an ideal gas under adiabatic condition? [AIPMT (S) 2011]
  A)
   \[q\ne 0,\Delta T=0,W=0\]
  done clear
  B)
        \[q=0,\Delta T=0,W=0\]
  done clear
  C)
        \[q=0,\Delta T<0,W\ne 0\]
  done clear
  D)
   \[q=0,\Delta T\ne 0,W=0\]
  done clear
  View Answer play_arrow

• question_answer59)  

  Enthalpy change for the reaction,

  \[4H(g)\xrightarrow[{}]{{}}2{{H}_{2}}(g)\] is \[\text{ }869.6\text{ }kJ\]

  The dissociation energy of \[H-H\] bond is

  A)
   \[-869.6\,kJ\]    
  done clear
  B)
        \[+\,434.8\,kJ\]
  done clear
  C)
   \[+\,217.4\,kJ\]
  done clear
  D)
        \[-\,434.8\,kJ\]
  done clear
  View Answer play_arrow

• question_answer60) 

  Consider the following processes \[\Delta H\,(kJ/\,mol)\]                                                        [AIPMT (M) 2011]

  \[1/2A\to B\]                  + 150

  \[3B\to 2C+D\]              - 125

  \[E+A\to 2D\]                + 350

  For \[B+D\to E+2C,\Delta H\] will be

  A)
   525 kJ/mol    
  done clear
  B)
        - 175 kJ/mol
  done clear
  C)
   - 325 kJ/mol    
  done clear
  D)
        325 kJ/mol
  done clear
  View Answer play_arrow

• question_answer61) In which of the following reactions, standard reaction entropy changes \[(\Delta {{S}^{o}})\] is positive and standard Gibb's energy change \[(\Delta {{S}^{o}})\] decreases    sharply   with    increasing temperature?     [AIPMT (S) 2012]
  A)
   \[C\,(\text{graphite})+\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}CO(g)\]
  done clear
  B)
   \[CO(g)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}C{{O}_{2}}(g)\]
  done clear
  C)
   \[Mg(s)+\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}MgO(s)\]
  done clear
  D)
   \[\frac{1}{2}C(\text{graphite})+\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}\frac{1}{2}C{{O}_{2}}(g)\]
  done clear
  View Answer play_arrow

• question_answer62) The enthalpy of fusion of water is kcal/mol. The molar entropy change for the melting of ice at \[{{0}^{o}}C\] is                            [AIPMT (S) 2012]
  A)
   10.52 cal/(mol K)
  done clear
  B)
       21.04 cal/(mol K)
  done clear
  C)
   5.260 cal/ (mol K)
  done clear
  D)
       0.526 cal/(mol K)
  done clear
  View Answer play_arrow

• question_answer63) Standard enthalpy of vaporization \[{{\Delta }_{vap}}{{H}^{\Theta }}\] for water at \[{{100}^{o}}C\] is \[40.66\,kJ\,mo{{l}^{-1}}\]. The internal energy of vaporisation .of water at \[{{100}^{o}}C\] (in kJ \[mo{{l}^{-1}}\] is (Assume water vapour to behave like an ideal gas). [AIPMT (S) 2012]
  A)
   + 37.56        
  done clear
  B)
   - 43.76
  done clear
  C)
   + 43.76          
  done clear
  D)
        + 40.66
  done clear
  View Answer play_arrow

• question_answer64) Equal volumes of two monoatomic gases, A and B, at same temperature and pressure are mixed. The ratio of specific heats \[(cp/cv)\] of the mixture will be                                                                [AIPMT (M) 2012]
  A)
   0.83   
  done clear
  B)
        1.50
  done clear
  C)
   3.3      
  done clear
  D)
        1.67
  done clear
  View Answer play_arrow

• question_answer65) 

  The Gibbs’ energy for the decomposition of\[A{{l}_{2}}{{O}_{3}}\] at \[{{500}^{o}}C\] is as follows

  \[\frac{2}{3}A{{l}_{2}}{{O}_{3}}\xrightarrow[{}]{{}}\frac{4}{3}Al+{{O}_{2}};\] \[{{\Delta }_{r}}G=+\,960\,kJ\,mo{{l}^{-1}}\]

  The potential difference needed for the electrolytic reduction of aluminium oxide \[(A{{l}_{2}}{{O}_{3}})\] at \[{{500}^{o}}C\] is at least             [AIPMT (M) 2012]

  A)
   4.5 V             
  done clear
  B)
        3.0 V   
  done clear
  C)
   2.5 V                  
  done clear
  D)
        5.0 V
  done clear
  View Answer play_arrow

• question_answer66) 

  Using   the   Gibbs   energy   change                                                                                  [AIPMT 2014]

  \[\Delta {{G}^{{}^\circ }}=+63.3\,\,kJ\] for the following reaction,\[A{{g}_{2}}C{{O}_{3}}(s)r\,2A{{g}^{+}}(aq)+CO_{3}^{2-}(aq)\]

  the \[{{K}_{sp}}\] of \[A{{g}_{2}}C{{O}_{3}}(s)\] in water at \[{{25}^{o}}C\] is \[(R=8.314\,J{{K}^{-1}}\,mo{{l}^{-1}})\]

  A)
   \[3.2\times {{10}^{-26}}\]       
  done clear
  B)
        \[8.0\times {{10}^{-12}}\]
  done clear
  C)
   \[2.9\times {{10}^{-3}}\]        
  done clear
  D)
        \[7.9\times {{10}^{-2}}\]
  done clear
  View Answer play_arrow

• question_answer67) Which of the following statements is correct for the spontaneous absorption of a gas?               [AIPMT 2014]
  A)
   \[\Delta S\] is negative and therefore, \[\Delta H\] should be highly positive
  done clear
  B)
   \[\Delta S\] is negative and therefore, \[\Delta H\] should be highly negative
  done clear
  C)
   \[\Delta S\] is positive and therefore, \[\Delta H\] should be negative
  done clear
  D)
   \[\Delta S\] is positive and therefore, \[\Delta H\] should also be highly positive.
  done clear
  View Answer play_arrow

• question_answer68) 

  For the reaction,\[{{X}_{2}}{{O}_{4}}(l)\to 2X{{O}_{2}}(g)\]

  \[\Delta U=2.1\,kcal,\,\,\Delta S=20\,cal\,\,{{K}^{-1}}\] at 300 K.

  Hence, \[\Delta G\] is                                                                                               [AIPMT 2014]

  A)
   2.7 kcal          
  done clear
  B)
        -2.7 kcal          
  done clear
  C)
   9.3 kcal          
  done clear
  D)
        -9.3 kcal
  done clear
  View Answer play_arrow

• question_answer69) Which of the following organic compounds has same hybridisation as its combustion product\[-(C{{O}_{2}})\]?            [AIPMT 2014]
  A)
   Ethane
  done clear
  B)
        Ethyne
  done clear
  C)
   Ethene             
  done clear
  D)
   Ethanol
  done clear
  View Answer play_arrow

• question_answer70) Which of the following statements is correct for a reversible process in a state of equilibrium? [NEET 2015 ]
  A)
   \[\Delta G=-2.30\,\,RT\,\,\,\log \,\,K\]
  done clear
  B)
   \[\Delta G=2.30\,\,RT\,\,\,\log \,\,K\]
  done clear
  C)
   \[\Delta {{G}^{o}}=-2.30\,\,RT\,\,\,\log \,\,K\]
  done clear
  D)
   \[\Delta {{G}^{{}^\circ }}=2.30\,\,RT\,\,\,\log \,\,K\]
  done clear
  View Answer play_arrow

• question_answer71) The heat of combustion of carbon to \[C{{O}_{2}}\] is \[-393.5\,\,kJ/mol\]. The heat released upon the formation of 35.2 g of \[C{{O}_{2}}\] from carbon and oxygen gas is                                                      [NEET 2015 (Re)]
  A)
   - 315 kJ
  done clear
  B)
        + 315 kJ
  done clear
  C)
   - 630 kJ           
  done clear
  D)
        - 3.15 kJ
  done clear
  View Answer play_arrow

• question_answer72) 

  The formation of the oxide ion \[{{O}^{2-}}(g),\] from oxygen atom requires first an exothermic and then an endothermic step as shown below,                                                                                           [NEET 2015 (Re)]

  \[O(g)+{{e}^{-}}\to {{O}^{-}}(g);\,\,{{\Delta }_{f}}{{H}^{{}^\circ }}=-141\,\,KJ\,mo{{l}^{-1}}\]

  \[{{O}^{-}}(g)+{{e}^{-}}\xrightarrow{\,}\,{{O}^{2-}}\,(g);\,{{\Delta }_{f}}{{H}^{o}}\]\[=\,\,+\,780\,\,kJ\,m\,o{{l}^{-1}}\]

  Thus, process of formation of \[{{O}^{2-}}\] in gas phase is unfavourable even though \[{{O}^{2-}}\] is isoelectronic with neon. It is due to the fact that

  A)
   electron repulsion outweighs the stability gained by achieving noble gas configuration
  done clear
  B)
   \[{{O}^{-}}\] ion has comparatively smaller size than oxygen atom
  done clear
  C)
   Oxygen is more electronegative
  done clear
  D)
   addition of electron in oxygen result in large size of the ion
  done clear
  View Answer play_arrow

• question_answer73) The correct thermodynamic conditions for the spontaneous reaction at all temperatures is         [NEET - 2016]
  A)
   \[\Delta H<0\] and \[\Delta S=0\]
  done clear
  B)
        \[\Delta H>0\] and \[\Delta S<0\]
  done clear
  C)
   \[\Delta H<0\] and \[\Delta S>0\]
  done clear
  D)
   \[\Delta H<0\] and \[\Delta S<0\]
  done clear
  View Answer play_arrow

• question_answer74) 

  Consider the following liquid - vapour equilibrium.                                               [NEET - 2016]

  \[\text{Liquid }\,\text{Vapour}\]

  Which of the following relations is correct?

  A)
   \[\frac{d\ell nG}{d{{T}^{2}}}=\frac{\Delta {{\Eta }_{v}}}{R{{T}^{2}}}\]
  done clear
  B)
        \[\frac{d\ell nP}{dT}=\frac{-\Delta {{\Eta }_{v}}}{RT}\]
  done clear
  C)
   \[\frac{d\ell nP}{d{{T}^{2}}}=\frac{-\Delta {{\Eta }_{v}}}{{{T}^{2}}}\]
  done clear
  D)
        \[\frac{d\ell nP}{dT}=\frac{\Delta {{\Eta }_{v}}}{R{{T}^{2}}}\]
  done clear
  View Answer play_arrow

• question_answer75) A gas is allowed to expand in a well-insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. The change in internal energy \[\Delta U\] of the gas in joules will be [NEET-2017]
  A)
   +505 J            
  done clear
  B)
        1136.25 J
  done clear
  C)
   - 500 J
  done clear
  D)
        - 505 J
  done clear
  View Answer play_arrow

• question_answer76) For a given reaction, \[\Delta H=35.5\,kJ\,mo{{l}^{-1}}\] and \[\Delta S=83.6\,J{{K}^{-1}}\,mo{{l}^{-1}}.\] The reaction is spontaneous at : (Assume that \[\Delta H\] and \[\Delta S\] do not vary with temperature)     [NEET-2017]
  A)
   \[T>298\text{ }K\]       
  done clear
  B)
        \[T<425\text{ }K\]
  done clear
  C)
   \[T>425\,K\]    
  done clear
  D)
        All temperatures
  done clear
  View Answer play_arrow

• question_answer77) The bond dissociation energies of \[{{\text{X}}_{\text{2}}}\text{,}{{\text{Y}}_{\text{2}}}\] and \[\text{XY}\] are in the ratio of 1 : 0.5 : 1. \[\Delta \text{H}\] for the formation of XY is \[\text{--200 kJ mo}{{\text{l}}^{\text{--1}}}\]. The bond dissociation energy of \[{{\text{X}}_{\text{2}}}\] will be                         [NEET - 2018]
  A)
   \[\text{800 kJ mo}{{\text{l}}^{\text{--1}}}\]
  done clear
  B)
        \[\text{100 kJ mo}{{\text{l}}^{\text{--1}}}\]
  done clear
  C)
   \[\text{200 kJ mo}{{\text{l}}^{\text{--1}}}\]
  done clear
  D)
        \[\text{400 kJ mo}{{\text{l}}^{\text{--1}}}\]
  done clear
  View Answer play_arrow

• question_answer78) In which case change in entropy is negative?                                                           [NEET 2019]
  A)
   Sublimation of solid to gas
  done clear
  B)
   \[2H(g)\to {{H}_{2}}(g)\]
  done clear
  C)
   Evaporation of water
  done clear
  D)
   Expansion of a gas at temperature
  done clear
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• question_answer79) Under isothermal condition, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is [Given that 1 L bar = 100 J]                                            [NEET 2019]
  A)
   25 J                
  done clear
  B)
        30 J
  done clear
  C)
   -30 J   
  done clear
  D)
        5 kJ
  done clear
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• question_answer80) For the reaction, \[2\,Cl\,(g)\xrightarrow{{}}~C{{l}_{2}}(g)\], the correct option is:                           [NEET 2020]
  A)
   \[{{\Delta }_{r}}H>0\] and \[{{\Delta }_{r}}S<0\]
  done clear
  B)
   \[{{\Delta }_{r}}H<0\] and \[{{\Delta }_{r}}S>0\]
  done clear
  C)
   \[{{\Delta }_{r}}H<0\] and \[{{\Delta }_{r}}S<0\]
  done clear
  D)
   \[{{\Delta }_{r}}H>0\] and \[{{\Delta }_{r}}S>0\]
  done clear
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• question_answer81) The correct option for free expansion of an ideal gas under adiabatic condition is                     [NEET 2020]
  A)
   \[q=0,\text{ }\Delta T<0\] and \[w>0\]
  done clear
  B)
   \[q<0,\text{ }\Delta T=0\] and \[w=0\]
  done clear
  C)
   \[q>0,\text{ }\Delta T>0\] and \[w>0\]
  done clear
  D)
   \[q=0,\text{ }\Delta T=0\] and \[w=0\]
  done clear
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