Chemistry - Thermochemistry Question with Solution | TestHub

ChemistryThermochemistryBond EnthalpyMedium2 minQB
ChemistryMediumsingle choice
Passage / Comprehension

The bond dissociation enthalpy of the first H-S bond in hydrogen sulphide is 376.0 kJ/mol. The enthalpies of formation of H2S(g) and S(g) are -20.0 and 277.0 kJ/mol, respectively. The bond dissociation enthalpy of H-H bond is 436.0 kJ/mol.

The bond dissociation enthalpy of the free radical HS is

Options:

Answer:
C
Solution:

The enthalpy change for the reaction HS tarrow H + S is calculated as follows:

Δ H = Δ Hf(H) + Δ Hf(S) - Δ Hf(HS)

Substituting the given values:

Δ H = 218 kJ/mol + 277 kJ/mol - 138 kJ/mol = 357 kJ/mol

This corresponds to option (c).

Stream:JEESubject:ChemistryTopic:ThermochemistrySubtopic:Bond Enthalpy
⏱ 2mℹ️ Source: QB

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