Question

why does helium balloon flots in air

Answer 1

The helium balloon displaces an amount of air (just like the empty bottle displaces an amount of water). As long as the weight of the heliumplus the balloon fabric is lighter than the air it displaces, the balloon will float in the air. It turns out that helium is a lot lighter than air.

Answer 2

Helium is found most around the sun, least on the earth.... Due it's low wt it floats on air......
It may be the answer mate..... Don't know exactly