Why is hydrogen used to inflate hot air balloons?

Any gas.

Helium is a gas used to inflate lighter than air balloons.

Helium is used to inflate balloons because it is lighter than air and that makes the balloon float.

'Hot air' balloons don't use hydrogen. They use hot air. Balloons that use hydrogen are not referred to as 'hot air' balloons. The only balloons that can accurately be referred to as 'hot air' balloons are the members of the balloon population that derive their lift/buoyancy from the presence of hot air. Of course, if a balloon used no hot air, then it could freely be referred to as a 'hydrogen' balloon, a 'helium' balloon…

Hydrogen is lighter. This is why balloons rise, they have hydrogen in them. ____ Hydrogen is lighter than air, and has been used in large balloons in the past (such as the Hindenburg). However, Helium is also lighter than air, and is what is used in most balloons today, since it is not flammable.

because it helps it fly in air

yes, it can inflate a balloon. In fact, that's what most people use to inflate their balloons. helium-filled balloons float, unlike balloons that are inflated using regular air. This is because helium has a lower density that air, therefore making it lift upwards.

Helium is the most used gas for balloons; sometimes hot air and rarely hydrogen.

Hydrogen was used in air balloons at older times. but at present we use helium gas in air balloons . helium is an inert gas.

Hydrogen gas was used in air balloons because it is much less dense than air and therefore rises, taking the balloon with it. it is unfortunately also very explosive so not used often anymore.

Gases used are helium, hot air (normal air for children balloons) or hydrogen. The safest is helium but also is the most expensive.

Helium (Hydrogen could also be used but this is flamable). Not some balloons are also kept aloft using hot air.

Hydrogen, until the Hindenburg,then everyone realized that "Hey, Hydrogen isn't that safe to use!" Hot air balloons, you mean?? Just air that is hot. Actual hand balloons and such? Helium or again, just air. Helium floats better because it is lighter than the surrounding air around it. Helium and air are still used in both.

They both fill up with air. When you inhale, air enters the lungs and they inflate.

Helium is used to fill balloons instead of oxygen or hydrogen is because helium is lighter than air while oxygen and hydrogen are denser so they do not make the balloon float in the air because of gravity.