A student takes some zinc granules in a test tube and adds dilute hydrochloric acid to it . He would observe that the colour of the zinc granules changes to

Options

A. white
B. black
C. brown
D. yellow .

Explanation

To solve the question, we will analyze the reaction between zinc granules and dilute hydrochloric acid step by step.

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The student takes zinc granules (Zn) and adds dilute hydrochloric acid (HCl) to them.

2. **Understand the Reaction**:
- When zinc reacts with dilute hydrochloric acid, a chemical reaction occurs. The balanced chemical equation for this reaction is:
\[ \text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \]
- Here, zinc chloride (ZnCl₂) is formed, and hydrogen gas (H₂) is released.

3. **Observe the Changes**:
- Initially, zinc granules are shiny and metallic. As the reaction proceeds, the zinc granules will start to dissolve in the acid.
- The formation of zinc chloride in solution does not change the color of the solution; it remains colorless.

4. **Color Change of Zinc Granules**:
- As the zinc reacts and dissolves, the surface of the zinc granules may appear to change color. The zinc granules may take on a darker appearance due to the formation of zinc chloride and the release of hydrogen gas.

5. **Final Observation**:
- The final observation is that the color of the zinc granules changes, and they may appear blackish due to the reaction. The solution remains colorless.

### Conclusion:
- The color of the zinc granules changes to blackish, while the solution remains colorless.