Explanation:

- Option 1: Light yellow

- Hydrogen gas is not light yellow in color.

- Pure hydrogen is invisible to the human eye.

- Option 2: Orange

- Orange colored gases are often compounds or pollutants.

- Hydrogen gas does not exhibit this property.

- Option 3: Black

- Black gases typically pertain to dense smoke or certain particulate matter.

- Hydrogen gas does not appear black.

- Option 4: Colourless

- Hydrogen gas is indeed colorless.

- It is invisible and without color in its pure gaseous state.

- CORRECT ANSWER

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