Which of the following has standard enthalpy | vedclass

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(A) The standard enthalpy of formation $(\Delta_fH^\circ)$ of an element in its most stable state at $298 \ K$ and $1 \ 	ext{bar}$ pressure is define

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$Hg\,(l)$

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(A) The standard enthalpy of formation $(\Delta_fH^\circ)$ of an element in its most stable state at $298 \ K$ and $1 \ 	ext{bar}$ pressure is defined as zero.$Hg\,(l)$ is the most stable state of mercury at $298 \ K$.$Xe\,(g)$ is the most stable state of xenon at $298 \ K$.$Br_2\,(l)$ is the most stable state of bromine at $298 \ K$.$S_{	ext{monoclinic}}$ is an allotrope of sulfur,but its most stable form at $298 \ K$ is $S_{	ext{rhombic}}$.Since the question asks for which of the following has a standard enthalpy of formation equal to zero,and $Hg$,$Xe$,and $Br_2$ are all in their standard states,this question contains multiple correct options. However,in standard textbook contexts,$Hg\,(l)$,$Xe\,(g)$,and $Br_2\,(l)$ are all correct. If forced to choose one,$Hg\,(l)$ is a standard reference.

Which of the following has standard enthalpy of formation equal to zero?

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