Thermodynamics And Thermochemistry Result Question 8
8. The species which by definition has zero standard molar enthalpy of formation at $298 \mathrm{~K}$ is
(2010)
(a) $\mathrm{Br} _2(g)$
(b) $\mathrm{Cl} _2(g)$
(c) $\mathrm{H} _2 \mathrm{O}(g)$
(d) $\mathrm{CH} _4(g)$
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Answer:
Correct Answer: 8. ( b )
Solution:
- Elements in its standard state have zero enthalpy of formation. $\mathrm{Cl}_2$ is gas at room temperature, therefore $\Delta H_f^{\circ}$ of $\mathrm{Cl}_2(\mathrm{~g})$ is zero.
BETA
