Question

Assertion :
The enthalpy of formation of HCl is equal to the bond energy of HCl.
Reason :
Enthalpy of formation and bond energy both involve the formation of one mole of HCl from the elements.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
b.) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c.) Assertion is correct but Reason is incorrect
d.) Both Assertion and Reason are incorrect

Answer 1

Hint: So, for finding the relation between enthalpy of formation and bond energy relation we will see their definitions and then relate enthalpy and bond energy of HCl.

Complete step by step solution:
We know that the enthalpy of formation is the standard reaction enthalpy for the formation of the compound from its elements in their most stable reference states at the known temperature and pressure. And the amount of heat absorbed or evolved when 1 mole of the substance is directly obtained from its constituent elements in their standard state.
The energy required to break the bond is known as bond dissociation energy. More precisely we can say that the amount of energy required to break one mole of bond of a particular type between the atoms. The bond dissociation energy of a diatomic molecule is also called bond energy. However, the bond dissociation energy depends upon the nature of bond and also the molecule in which the bond is present.

And here in case of HCl enthalpy of formation and bond energy involve the formation of one mole of HCl from the elements. So, here both reason and assertion are correct and option “A” is the correct option.

Note: Here, we should know the difference between bond energy and enthalpy of formation. And in the case of HCl there is single bond formation between H and Cl.