Home
Class 12
CHEMISTRY
Consider the following reactions: (a) ...

Consider the following reactions:
(a) `H_(aq)^(+) +OH_(aq)^(-) to H_(2)O_((l)) triangleH=-X_(1) kJ mol^(-1)`
(b) `H_(2(g))+1/2 O_(2)(g) to H_(2)O((l)), triangleH=-X_(2)"kJ mol"^(-1)`
(c) `CO_(2(g))+H_(2(g)) to CO_((g))+H_(2)O_(l))`
`triangleH=-X_(3)"kJ mol"^(-1)`
(d) `C_(2)H_(2(g))+5/2 O_(2)(g) to 2CO_(2)+H_(2)O_(l)`
`triangleH=+ X_(4)kJ mol^(-1)`
Enthalpy of formation of `H_2O` is

A

`+X_(1)"kJ mol"^(-1)`

B

`-X_(2)"kJ mol"^(-1)`

C

`+X_(3)"kJ mol"^(-1)`

D

`-X_(4)"kJ mol"^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
B
Heat of formation of `H_(2)O` equation is
`H_(2(g))+(1)/(2)rarr H_(2)O_((l)) , Delta H = -X_(2) kJ mol^(-1)`
Promotional Banner

Topper's Solved these Questions

  • THERMODYNAMICS

    ALLEN|Exercise EXERCISE -1B|22 Videos

  • THERMODYNAMICS

    ALLEN|Exercise EXERCISE -2|100 Videos

  • THERMODYNAMICS

    ALLEN|Exercise Questions|46 Videos

  • TEST PAPERS

    ALLEN|Exercise MATHEMATICS|2 Videos

  • Thermodynamics And Thermo Chemistry

    ALLEN|Exercise All Questions|40 Videos

Similar Questions

Explore conceptually related problems

Consider the following reactions : (a) H_((aq))^(+)+OH_((aq))^(-)=H_(2)O_((l)), Delta H= - X_(1)"kJ mol"^(-1) (b) H_(2(g))+(1)/(2)O_(2(g))=H_(2)O_((l)), Delta H= - X_(2)"kJ mol"^(-1) (c ) CO_(2(g))+H_(2(g))=CO_((g))+H_(2)O_((l))- X_(3)"kJ mol"^(-1) (d) C_(2)H_(2(g))+(5)/(2)O_(2(g))=2CO_(2(g))+H_(2)O_((l))+X_(4)"kJ mol"^(-1) Enthalpy of formation of H_(2)O_((l)) is :

Consider the following reactions: (i) H^(+)(aq)+OH^(-)(aq)rarrH_(2)O(l) , DeltaH=-X_(1)KJmol^(-1) (ii) H_(2)(g)+(1)/(2)O_(2)(g)rarrH_(2)O(l),DeltaH=-X_(2)KJmol^(-1) (iii) CO_(2)(g)+H_(2)(g)rarrCO(g)+H_(2)O(l) , DeltaH=-X_(3)KJmol^(-1) (iv) C_(2)H_(2)(g)+(5)/(2)O_(2)(g)rarr2CO_(2)(g)+H_(2)O(l) , DeltaH=+X_(4)KJmol^(-1) Enthanlpy of formation of H_(2)O(l) is

Consider the following reaction :- (a) H_(aq)^(+)+CI_(aq)^(-)toHCI_(l),DeltaH=-X_(1) KJmol^(-1) (b) H_2(g)^(+)+CI_2(g)to2HCI_(l),DeltaH=-X_(2) KJmol^(-1) ( c) (1)/(2)H_(2(g))+(1)/(2)CI_(2(g))toHCI_(l),DeltaH=-X_(3) KJmol^(-1) (d) H_((g))+CI_((g))toHCI_(l),DeltaH=-X_(4) KJmol^(-1) Enthalpy of formation of HCI_(l) is :-

H_2(g) + 1/2 O_2(g) to H_2O (l), DeltaH = - 286 kJ 2H_2(g) + O_2(g) to 2H_2O (l), DeltaH = …kJ

Consider the following reactions: I. C(s) + 1/2 O_(2)(g) rarr CO(g)," "Delta H_(1) = x_(1) II. CO(g) + 1/2 O_(2)(g) rarr CO_(2)(g), " "Delta H_(2) = x_(2) III. C(s) + CO_(2)(g) rarr 2CO(g)," "Delta H_(3) = x_(3) Select the correct statements:

Calculate enthalpy of formation of methane (CH_4) from the following data : (i) C(s) + O_(2)(g) to CO_(2) (g) , Delta_rH^(@) = -393.5 KJ mol^(-1) (ii) H_2(g) + 1/2 O_(2)(g) to H_(2)O(l) , Deta_r H^(@) = -285.5 kJ mol^(-1) (iii) CH_(4)(g) + 2O_(2)(g) to CO_(2)(g) + 2H_(2)O(l), Delta_(r)H^(@) = -890.3 kJ mol^(-1) .

H_(2)(g)+(1)/(2)O_(2)(g)rarrH_(2)O(l), DeltaH =- 286 kJ 2H_(2)(g)+O_(2)(g)rarr2H_(2)O(l)……………kJ(+-?)

Form the thermochemical reactions. C(graphite) +1//2 O_(2)(g) to CO(g), triangleH=-110.5kJ CO(g)+1//2O_(2)(g) to CO_(2)(g), triangleH=-283.2kJ The enthalpy ofreaction of C(graphite) +O_(2)(g) to CO_(2)" is "

Calculate the heat of formation of methane in kcalmol^(-1) using the following thermo chemical reactions C(s)+O_(2)toCO_(2)(g) , DeltaH=-94.2 kcal mol^(-1) H_(2)(g)+1/2O_(2)(g)toH_(2)O(l) , DeltaH=-68.3 kcal mol^(-1) CH_(4)(g)+2O_(2)(g)toCO_(2)(g)+2H_(2)O(l) , DeltaH=-210.8 kcal mol^(-1)

Given that: i. C(s) + O_(2)(g) rarr CO_(2)(g) , DeltaH =- 94.05 kcal ii. H_(2)(g) +(1)/(2) O_(2)(g) rarr H_(2)O(l), DeltaH =- 68.32 kcal iii. C_(2)H_(2)(g) +(5)/(2) O_(2)(g) rarr 2CO_(2)(g) +H_(2)O(l),DeltaH =- 310.62 kcal The heat of formation fo acetylene is

ALLEN-THERMODYNAMICS -EXERCISE -1A
  1. For a spontaneous process the correct statement is

    Text Solution

    |

  2. The enthalpy change (Delta H) for the reaction, N(2)(g)+3H(2)(g)to 2NH...

    Text Solution

    |

  3. Consider the following reactions: (a) H(aq)^(+) +OH(aq)^(-) to H(2)O...

    Text Solution

    |

  4. Given that bond energies of H–H and Cl–Cl are 430 kJ mol^(-1) and 240...

    Text Solution

    |

  5. Bond dissociation enthalpy of H(2), Cl(2) and HCl are 434, 242 and 431...

    Text Solution

    |

  6. For the gas phase reaction, PCl(5)(g) hArr PCl(3)(g) + Cl(2)(g) Wh...

    Text Solution

    |

  7. Which of the following are not a constant value between two given ther...

    Text Solution

    |

  8. From the following bond energies: H-H bond energy: 431.37KJmol^(-1) ...

    Text Solution

    |

  9. The values of DeltaH and DeltaS for the reaction, C("graphite")+CO(2...

    Text Solution

    |

  10. For vaporization of water at 1 atmospheric pressure the values of Delt...

    Text Solution

    |

  11. Three moles of an ideal gas expanded spontaneously into vaccum. The wo...

    Text Solution

    |

  12. The following two reactions are known : Fe(2)O(3)(s) + 3 CO(g) rightar...

    Text Solution

    |

  13. Standard entropies of X(2), Y(2) and XY(3) are 60, 40 and 50 JK^(–1) m...

    Text Solution

    |

  14. Intensive property is :-

    Text Solution

    |

  15. In which of following there is decrease in entropy :-

    Text Solution

    |

  16. Which of the following is not a state function?

    Text Solution

    |

  17. If the enthalpy change for the transition of liquid water to steam is ...

    Text Solution

    |

  18. Enthalpy change for the reaction, 4H(g) to 2H2(g) is -869.6 kJ Th...

    Text Solution

    |

  19. Which of the following is correct option for free expansion of an idea...

    Text Solution

    |

  20. Consider the following processes : {:(,DeltaH(kJ//"mol")),(1/2ArarrB...

    Text Solution

    |