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 composed of both organic and inorganic materials. The organic part primarily consists of collagen, which provides flexibility, while the inorganic part mainly consists of calcium salts, which provide hardness and rigidity.

2. **Effect of Dilute Hydrochloric Acid**:
- When a frog's bone is placed in dilute hydrochloric acid, the acid reacts with the inorganic salts present in the bone. These inorganic salts, such as calcium carbonate and calcium phosphate, are responsible for the hardness of the bone.

3. **Dissolution of Inorganic Salts**:
- The hydrochloric acid dissolves these inorganic salts, leading to the loss of the bone's rigidity. As the inorganic components dissolve, the structure that provides strength and hardness to the bone is compromised.

4. **Resulting Change in Bone Properties**:
- With the inorganic salts removed, the organic matrix (collagen) remains intact. This means that while the bone loses its hardness, it retains some of its structural integrity due to the collagen.

5. **Final Outcome**:
- As a result of this process, the bone becomes flexible. It does not turn black, break into pieces, or shrink significantly; rather, it simply loses its hardness and becomes pliable.

### Conclusion:
- Therefore, if the bone of a frog is kept in dilute hydrochloric acid, it will become flexible.