" Enthalpy of a reaction is given by: "

Enthalpy of a reaction is given as:

If the change in enthalpy of a reaction in absence of a catalyst is "xkJ.mol"^(-1) what will be the change in enthalpy of the reaction in the presence of a catalyst?

Define enthalpy of reaction.

What is enthalpy of a reaction? Explain the standard enthalpy of a reaction.