You get free hydrogen in the hydrogensilesquioxane process.

This recipe makes 12 HCl and requires 4 trichlorosilane. However, 4 trichlorosilane requires 3 HCl:

But each trichlorosilane gives 2 hydrogen, as shown above. Conceivably, you could say that the hydrogen is coming from the water, I guess.

actually yeah that's where the hydrogen is coming from jk ignore me

just kidding the hydrogen comes from the water