Whaat happens if the bone of a frog is kept in dilute hydrochloric acid?

Options

A. It becomes flexible
B. It turns black
C. It breaks into pieces
D. It shrinks

Explanation

### Step-by-Step Solution:

1. **Understanding the Composition of Bone**:
- Bones are made up of a hard mineral component (mainly calcium phosphate) and an organic matrix (primarily collagen). The mineral component gives bones their rigidity and strength.

**Hint**: Remember that bones have both a hard and a soft component.

2. **Effect of Dilute Hydrochloric Acid**:
- When a bone is placed in dilute hydrochloric acid, the acid reacts with the mineral salts present in the bone. Hydrochloric acid is a strong acid that can dissolve calcium phosphate.

**Hint**: Think about what happens when acids react with minerals.

3. **Decalcification Process**:
- The process of dissolving the mineral salts in the bone is known as decalcification. As the mineral content is removed, the organic matrix remains intact.

**Hint**: This process leaves behind the soft tissue structure of the bone.

4. **Resulting Change in the Bone**:
- After the decalcification process, the bone becomes soft and flexible because the rigid mineral component has been dissolved, leaving only the organic matrix.

**Hint**: Consider how the properties of the bone change when its mineral content is removed.

5. **Conclusion**:
- Therefore, the correct answer to the question is that the bone of a frog, when kept in dilute hydrochloric acid, becomes flexible.

**Hint**: Look for the option that describes a change in flexibility.

### Final Answer:
The bone of a frog kept in dilute hydrochloric acid becomes flexible.