You can't tell if a gas is hydrogen just by looking at it or smelling it. It's colorless, odorless, and tasteless. Here's how you can identify hydrogen gas:

1. Chemical Tests:

* Burning Test:

- Flammability: Hydrogen is highly flammable. It will burn with a pale blue flame in the presence of oxygen.

- Popping Sound: When a mixture of hydrogen and air is ignited, it produces a characteristic popping sound.

* Reaction with Copper Oxide:

- Hydrogen gas reacts with heated copper oxide to produce copper metal and water. This reaction can be observed by the change in color of the copper oxide from black to reddish-brown.

2. Physical Tests:

* Density: Hydrogen is the lightest element, with a density of about 0.0899 grams per liter. This means it's much less dense than air. If you have a container of unknown gas, you could compare its density to air's density to get an idea.

* Solubility: Hydrogen is only slightly soluble in water.

* Spectroscopy: If you have advanced equipment, you can analyze the light emitted by the gas using spectroscopy. This method can identify specific elements based on their unique spectral lines.

Important Notes:

* Safety: Hydrogen is extremely flammable and can be explosive in certain concentrations. Never conduct these tests without proper safety precautions and knowledge of handling flammable materials.

* Professional Testing: For reliable identification of hydrogen gas, it's always best to consult with a professional chemist or lab.

Let me know if you have any other questions!