Question

The enthalpy of reaction for the reaction :

2H₂(g) + O₂(g) → 2H₂O(l) is Δ_rH^Θ = – 572 kJ mol^–1.

What will be standard enthalpy of formation of  H₂O (l ) ?

Answer 1

According to the definition of standard enthalpy of formation, the enthalpy change for the following reaction will be standard enthalpy of formation of H₂O (l)

or the standard enthalpy of formation of H₂O(l ) will be half of the enthalpy of the given equation i.e., Δ_rH^Θ is also halved.