For gaseous hydrogen atoms at 298 K is +217 .
kJ.mol^-¹,The standard enthalpy of formation can be best written as:

Question

For gaseous hydrogen atoms at 298 K is +217 . kJ.mol^-¹,The standard enthalpy of formation can be best written as:

Quizplus · Accepted Answer

The standard enthalpy of formation is defined for the formation of one mole of a compound from its elements in their standard states. The correct expression should show the formation of the compound from its elements, not the decomposition of the compound into its elements. However, the given question seems to contain formatting errors, making it difficult to interpret the intended chemical species correctly. Based on the standard definition, choice B is conceptually correct as it implies the reverse process of forming a compound from its elemental form, which aligns with the concept of enthalpy of formation, despite the apparent formatting issues.

For Gaseous Hydrogen Atoms at 298 K Is +217 →\rightarrow→ H2(g) B) ½H2(g)

For Gaseous Hydrogen Atoms at 298 K Is +217 $\rightarrow$ H₂(g)
B) ½H₂(g)