Home
Class 12
CHEMISTRY
Which of the following reactions is Delt...

Which of the following reactions is `Delta H` less than `Delta E` ?

A

`C_(12)H_(22)O_(11)(s)+6O_(2)(g)rarr 6CO_(2)(g)+6H_(2)O(l)`

B

`2SO_(2)(g)+O_(2)(g)rarr 2SO_(3)(g)`

C

`N_(2)O_(4)(g)rarr 2NO_(2)(g)`

D

`N_(2)(g)+O_(2)(g)rarr 2NO(g)`

Text Solution

AI Generated Solution

The correct Answer is:
To determine which reaction has \( \Delta H < \Delta E \), we need to analyze the reactions provided and calculate the change in the number of gaseous moles (\( \Delta N_G \)) for each reaction. This will help us use the relationship between enthalpy change (\( \Delta H \)) and internal energy change (\( \Delta E \)). ### Step-by-Step Solution: 1. **Understanding the Relationship**: The relationship between the change in enthalpy (\( \Delta H \)) and the change in internal energy (\( \Delta E \)) is given by: \[ \Delta H = \Delta E + \Delta N_G \cdot R \cdot T \] where \( R \) is the gas constant and \( T \) is the temperature. 2. **Calculating \( \Delta N_G \)**: \( \Delta N_G \) is calculated as the difference between the number of moles of gaseous products and the number of moles of gaseous reactants. 3. **Analyzing Each Reaction**: - **Reaction 1**: \[ C_{12}H_{22}O_{11(s)} + 6 O_{2(g)} \rightarrow 6 CO_{2(g)} + 6 H_{2}O_{(l)} \] - **Gaseous Products**: 6 (from \( CO_2 \)) - **Gaseous Reactants**: 6 (from \( O_2 \)) - \( \Delta N_G = 6 - 6 = 0 \) - Thus, \( \Delta H = \Delta E \) (not valid for \( \Delta H < \Delta E \)). - **Reaction 2**: \[ 2 SO_{2(g)} + O_{2(g)} \rightarrow 2 SO_{3(g)} \] - **Gaseous Products**: 2 (from \( SO_3 \)) - **Gaseous Reactants**: 3 (2 from \( SO_2 \) + 1 from \( O_2 \)) - \( \Delta N_G = 2 - 3 = -1 \) - Since \( \Delta N_G \) is negative, \( \Delta H < \Delta E \) (valid). - **Reaction 3**: \[ N_{2(g)}O_{4(g)} \rightarrow 2 NO_{(g)} \] - **Gaseous Products**: 2 (from \( NO \)) - **Gaseous Reactants**: 1 (from \( N_2O_4 \)) - \( \Delta N_G = 2 - 1 = 1 \) - Thus, \( \Delta H > \Delta E \) (not valid). - **Reaction 4**: \[ N_{2(g)} + O_{2(g)} \rightarrow 2 NO_{(g)} \] - **Gaseous Products**: 2 (from \( NO \)) - **Gaseous Reactants**: 2 (from \( N_2 \) and \( O_2 \)) - \( \Delta N_G = 2 - 2 = 0 \) - Thus, \( \Delta H = \Delta E \) (not valid). 4. **Conclusion**: The only reaction where \( \Delta H < \Delta E \) is the second reaction: \[ 2 SO_{2(g)} + O_{2(g)} \rightarrow 2 SO_{3(g)} \] ### Final Answer: The reaction for which \( \Delta H < \Delta E \) is: **Option B: \( 2 SO_{2(g)} + O_{2(g)} \rightarrow 2 SO_{3(g)} \)**
Promotional Banner

Topper's Solved these Questions

  • THERMODYNAMICS

    ALLEN|Exercise EXERCISE -3|108 Videos
  • THERMODYNAMICS

    ALLEN|Exercise EXERCISE -4|18 Videos
  • THERMODYNAMICS

    ALLEN|Exercise EXERCISE -1B|22 Videos
  • TEST PAPERS

    ALLEN|Exercise MATHEMATICS|2 Videos
  • Thermodynamics And Thermo Chemistry

    ALLEN|Exercise All Questions|40 Videos

Similar Questions

Explore conceptually related problems

Which of the following reactions is defines Delta_(f)H^(Theta) ?

Which of the reactions defined Delta_f H^@ ?

Which of the following reactions represents Delta H (hydration) :-

In which of the following Delta H = Delta U ?

Which of the following relations are correct if Delta H represents only magnitude ?

Under which of the following condition Delta H = Delta E ?

Which of the following has DeltaS^(@) greater than zero

For which of the following change Delta H!=Delta U ?

In which of the following changes, Delta H is always negative :

Which of the following represents heat of formation (Delta H_(f)) ?

ALLEN-THERMODYNAMICS -EXERCISE -2
  1. The heat of combustion of ethanol determined in a bomb calorimeter is ...

    Text Solution

    |

  2. The difference in Delta H and Delta E for the combustion of methane at...

    Text Solution

    |

  3. Which of the following reactions is Delta H less than Delta E ?

    Text Solution

    |

  4. For a reaction 2X(s)+2Y(s)rarr 2Cl(l)+D(g) The q(p) at 27^(@)C is -...

    Text Solution

    |

  5. The work done in ergs for the reversible expansion of one mole of an i...

    Text Solution

    |

  6. Two liters of N(2) at 0^(@)C and 5 atm pressure is expanded isothermal...

    Text Solution

    |

  7. Two moles of an ideal gas expand spontaneously into a vacuum. The work...

    Text Solution

    |

  8. One mole of a gas occupying 3dm^(3) expands against a constant externa...

    Text Solution

    |

  9. For which reaction from the following, DeltaS will be maximum?

    Text Solution

    |

  10. An adiabatic process is one in which :-

    Text Solution

    |

  11. Entropy means

    Text Solution

    |

  12. Delta S for the reaction : MgCO(3) rightarrow MgO(s) + CO(2)(g)

    Text Solution

    |

  13. Change in entropy is negative for

    Text Solution

    |

  14. In which reaction Delta S is positive :-

    Text Solution

    |

  15. When the egg is hard boiled, there

    Text Solution

    |

  16. If S^@" for "H(2), Cl2 and HCl are 0.13, 0.22 and 0.19" kJ K"^(-1)"mol...

    Text Solution

    |

  17. Which has the least entropy :

    Text Solution

    |

  18. When two gases are mixed the entropy :-

    Text Solution

    |

  19. The enthalpy of vaporization for water is 186.5 KJ mol^(−1) ,the entro...

    Text Solution

    |

  20. Calculate the enthalpy of vaporisation per mole for ethanol. Given Del...

    Text Solution

    |