Hess’s law is based on :

Options

A. Law of conservation of mass
B. Law of conservation of energy
C. First law of thermodynamics
D. None of the above

Explanation

**Step-by-Step Solution:**

1. **Understanding Hess's Law**: Hess's law, formulated by Russian chemist G. H. Hess in 1840, states that the total amount of heat evolved or absorbed in a chemical reaction is the same, regardless of whether the reaction occurs in one step or multiple steps.

2. **Key Concept**: The law emphasizes that the total heat change in a reaction depends solely on the nature of the initial reactants and the final products, not on the specific pathway taken to achieve the reaction.

3. **Relation to Energy Conservation**: Hess's law is fundamentally linked to the principle of conservation of energy, which is also a core concept in the first law of thermodynamics. This principle asserts that energy cannot be created or destroyed, only transformed from one form to another.

4. **Conclusion**: Therefore, Hess's law can be understood as an expression of the conservation of energy, indicating that the enthalpy change of a process is independent of the path taken from the initial state to the final state.

5. **Correct Answer**: Based on the explanation, Hess's law is based on the law of conservation of energy.

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