Which of the following equations corresponds to the definition of enthalpy of formation at `298K`?

Which of the following equations corresponds to the definition of enthalpy of formation at 298 K?

Which of the following equations corresponds to the enthalpy of combustion at 298K ?

Which of the following equations represents a reaction that provides the enthalpy of formation of CH_(3)Cl ?

Which of the following equation represents first enthalpy of ionization ?

Enthalpy of which of the following reactions does not represent the standard enthalpy of formation?

Which of the following are not correct at 298K ?

What is standard enthalpy of formation

Which of the following reactions represents the enthalpy of formation of water?

Standard enthalpy of formation is zero for