Why was the hydrogen atom able to attach to the oxygen atom but not the chlorine atom???

Chlorine has a higher electronegativity, but as it has a large atomic radius the electron density is spread out over a large area. This means that the electron density is too low to form proper hydrogen bonds, and will only be attracted via dipole-dipole attraction.

heat or electricity in the atmosphere- c.

false

because it does not have the potential to be entirely used up