Assertion: Chemical reactions are chemical changes.
Reason It does not tells about the state of substance.

Answer

To analyze the assertion and reason provided in the question, we will break down the concepts involved step by step.

### Step 1: Understanding the Assertion
- **Assertion:** Chemical reactions are chemical changes.
- **Explanation:** A chemical reaction involves the transformation of reactants into products, resulting in a change in the chemical composition of the substances involved. This change is what we refer to as a chemical change. For example, when hydrogen gas (H2) reacts with oxygen gas (O2), they form water (H2O), demonstrating a chemical change.

### Step 2: Understanding the Reason
- **Reason:** It does not tell about the state of the substance.
- **Explanation:** The statement implies that chemical reactions do not provide information about the physical state (solid, liquid, gas) of the substances involved. However, this is misleading. While a chemical reaction may not explicitly state the physical state of the reactants or products, it can be inferred from the context or the chemical equation itself. For example, in the reaction of hydrogen and oxygen, both are gases, and water is a liquid at room temperature.

### Step 3: Evaluating the Truth of Assertion and Reason
- The assertion is true because chemical reactions indeed represent chemical changes.
- The reason is false because chemical reactions can indicate the states of substances when represented in a balanced chemical equation.

### Conclusion
- **Final Evaluation:** The assertion is true, but the reason is false. Therefore, the correct answer is that the assertion is true and the reason is false.