The law of mass action was enunciated by

Options

A. Berthelot
B. Bodenstein
C. Graham
D. Guldberg and Waage.

Answer

To solve the question regarding who enunciated the law of mass action, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Law of Mass Action**:
- The law of mass action states that at equilibrium, the rate of a chemical reaction is proportional to the product of the concentrations of the reactants raised to the power of their respective stoichiometric coefficients. This implies that the ratio of the concentrations of products to reactants remains constant at equilibrium.

2. **Identifying Key Scientists**:
- The question asks us to identify which scientist is credited with formulating the law of mass action.

3. **Researching the Scientists**:
- The law of mass action is primarily attributed to two scientists: **Cato Maximilian Guldberg** and **Peter Waage**. They formulated this law in the 19th century.

4. **Selecting the Correct Answer**:
- Based on the information gathered, the correct answer to the question is that the law of mass action was enunciated by **Guldberg and Waage**.

### Final Answer:
The law of mass action was enunciated by Guldberg and Waage.

---