When dilute hydrochloric acid is added to granulated zinc placed in atest tube, the observation made is :

Options

A. the surface of the metal turns shining
B. the reaction mixture turns milky
C. odour of chlorine is observed
D. a colourless and odourless gas evolves with bubbles.

Explanation

**Step-by-Step Solution:**

1. **Identify the Reactants**: The reaction involves granulated zinc (Zn) and dilute hydrochloric acid (HCl).

2. **Write the Chemical Reaction**: When zinc reacts with hydrochloric acid, the chemical equation can be written as:
\[ \text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \]
This shows that zinc reacts with hydrochloric acid to produce zinc chloride (ZnCl2) and hydrogen gas (H2).

3. **Observe the Products**:
- Zinc chloride (ZnCl2) is formed as a white salt.
- Hydrogen gas (H2) is produced, which is colorless and odorless.

4. **Make Observations**:
- Bubbles will be observed in the test tube due to the evolution of hydrogen gas.
- The surface of the zinc will not turn shiny; instead, it will react and form a salt.
- The reaction mixture will not turn milky, as that would indicate the formation of calcium carbonate, which is not involved in this reaction.

5. **Conclusion**: The correct observation when dilute hydrochloric acid is added to granulated zinc is that colorless and odorless hydrogen gas evolves with bubbles.

**Final Answer**: The observation made is that colorless and odorless gas evolves with bubbles (hydrogen gas).

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