Which of the following is not a pure substance?

The enthalpy of the reaction is coming out to be -902 kJ.

Explanation:

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as

The equation used to calculate enthalpy change is of a reaction is:  

For the given chemical reaction:

The equation for the enthalpy change of the above reaction is:

We are given:

Putting values in above equation, we get:

Hence, the enthalpy of the reaction is coming out to be -902 kJ.