1. Tardigrade
  2. Question
  3. Chemistry
  4. In the given reaction, H 2(g) longrightarrow 2 H (g) ; Δ H=435.0 kJ mol -1 The enthalpy change is known as

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Q. In the given reaction,
$H _{2}(g) \longrightarrow 2 H (g) ; \Delta H=435.0\, kJ\, mol ^{-1}$ The enthalpy change is known as

Thermodynamics

Solution:

In the reaction,
$H _{2}(g) \longrightarrow 2 H (g) ; \Delta_{a} H^{\circ}=435\, kJ\, mol ^{-1}$
$H$-atoms are formed by breaking $H - H$ bond in dihydrogen. The enthalpy change in this process is known as enthalpy of atomisation, $\Delta_{a} H^{\circ}$.
In case of diatomic molecules like dihydrogen, the enthalpy of atomisation is also known as bond dissociation enthalpy.