Which statement is not true about `CO`?

Options

A. It is a colurless gas.
B. It is an odourless gas .
C. it is highly soluble in water .
D. It is a poisonous gas .

Answer

To determine which statement is not true about carbon monoxide (CO), we can analyze the properties and characteristics of CO based on the information provided.

### Step-by-Step Solution:

1. **Identify the Properties of Carbon Monoxide (CO)**:
- Carbon monoxide is a **colorless** gas.
- It is **odorless**.
- It combines with hemoglobin to form **carboxyhemoglobin**, which is more stable than oxyhemoglobin.
- It is known to be **poisonous** as it reduces the availability of oxygen to tissues.
- Carbon monoxide is **insoluble** in water.

2. **Evaluate the Statements**:
- **Statement 1**: CO is colorless. (True)
- **Statement 2**: CO is odorless. (True)
- **Statement 3**: CO is highly soluble in water. (False)
- **Statement 4**: CO is poisonous. (True)

3. **Identify the Incorrect Statement**:
- The statement that CO is **highly soluble in water** is incorrect. CO is actually **insoluble** in water.

4. **Conclusion**:
- The statement that is not true about carbon monoxide is that it is **highly soluble in water**.

### Final Answer:
The statement that is not true about CO is: **It is highly soluble in water.**

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