Hydrogen is.......... soluble in water.

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: We need to determine if hydrogen is soluble in water.

2. **Understand the Nature of Hydrogen**: Hydrogen (H₂) is a diatomic molecule that is non-polar in nature. This means that it does not have a positive or negative end.

3. **Understand the Nature of Water**: Water (H₂O) is a polar molecule. This means that it has a positive end (hydrogen atoms) and a negative end (oxygen atom).

4. **Apply the Rule of Solubility**: In chemistry, there is a principle known as "like dissolves like." This means that polar substances tend to dissolve in polar solvents, and non-polar substances tend to dissolve in non-polar solvents.

5. **Compare Hydrogen and Water**: Since hydrogen is non-polar and water is polar, they do not have similar properties.

6. **Conclude the Solubility**: Based on the principle of "like dissolves like," we can conclude that hydrogen is not soluble in water.

7. **Final Answer**: Therefore, the answer to the question is: Hydrogen is not soluble in water.

---