Yes, hydrogen is sparingly soluble in water.
Hydrogen gas does exhibit some solubility in water, but the amount that dissolves is very small. As referenced, hydrogen is considered "sparingly soluble," meaning only a tiny quantity will dissolve under normal conditions. Practically, this often translates to having "little, if any, solubility" from a macroscopic perspective.
Understanding Sparingly Soluble
The term "sparingly soluble" is used in chemistry to describe substances that do dissolve in a solvent, but only to a very limited extent. Unlike highly soluble substances (like salt in water) or insoluble substances (like sand in water), sparingly soluble materials fall somewhere in between, leaning towards the insoluble side.
For hydrogen in water:
- The solubility is quite low compared to many other gases like carbon dioxide or ammonia.
- Factors like temperature and pressure influence gas solubility. Lower temperatures and higher pressures generally increase gas solubility, but hydrogen's solubility remains low even under varying conditions.
Practical Demonstration: Water Displacement
The low solubility of hydrogen in water is practically demonstrated in laboratory procedures. When hydrogen gas is produced during a chemical reaction, it is commonly collected using the water displacement method.
- In this method, a collecting vessel (like an inverted measuring cylinder or test tube) is filled with water and placed over the outlet where the hydrogen gas is being generated.
- As the hydrogen gas is produced, it bubbles up through the water and collects at the top of the inverted vessel, displacing the water downwards.
- This method works effectively precisely because very little hydrogen dissolves in the water as it passes through. If hydrogen were highly soluble, significant amounts would dissolve in the water, and the gas could not be efficiently collected this way.
This collection technique directly supports the statement that hydrogen has little, if any, practical solubility in water.
