Is Hydrogen a colorless gas?

Yes, it is colorless. This is what elementary chemistry tells you. But people may be wondering why they are adding a color attribute to hydrogen.

The color attribute of hydrogen comes about by the way it is produced on an industrial scale. There are three colors presently:

Grey hydrogen:

Basically from fossil fuels such as coal or natural gas.

https://www.coalage.com/features/hydrogen-from-coal/#:~:text=H%202%20produced%20by%20steam%20methane%20reforming%20%28SMR%29,hydrogen%20that%20includes%20carbon%20abatement%2C%20such%20as%20CCUS.

https://tinyurl.com/yey9fegt

By far most of the hydrogen presently produced/used is grey hydrogen.

Green hydrogen:

Hydrogen from Electrolysis of water.

This is completely free of carbon in its production.

http://www.chem.gla.ac.uk/cronin/media/papers/Chisholm-Chapter_16_2016.pdf#:~:text=The%20production%20of%20hydrogen%20from%20water%20via%20electrolysis,has%20two%20main%20applications%20as%20an%20energy%20vector.

or

https://tinyurl.com/4y6hektf

Blue hydrogen:

It is similar to Grey hydrogen but the carbon in the process is captured and stored (so-called carbon neutral).

https://www.msn.com/en-us/news/technology/blue-gas-could-become-a-tesla-killer/ar-BB1dOsgr#:~:text=So-called%20%27blue%27%20hydrogen%20is%20the%20name%20given%20to,water%20are%20converted%20into%20hydrogen%20and%20carbon%20monoxide.

https://tinyurl.com/e5k7zrxe