In which of the following conditions, the distance between the molecules of hydrogen gas would increase?

i)       Increasing pressure of hydrogen contained in a closed container

ii)     Some hydrogen gas leaking out of the container

iii)   Increasing the volume of the container of hydrogen gas

iv)   Adding more hydrogen gas to the container without increasing the volume of the container.

If some hydrogen gas leaks out of the container and on increasing the volume of the container of hydrogen gas the distance between the molecules of hydrogen gas would increase.
When hydrogen gas leaks from the container, the molecules of the remaining gas have more free space. As a result, the distance between the gas molecules grows. The distance between molecules grows as the volume of the container grows. When you heat them, you essentially give them kinetic energy, which increases their speed and thus the distance between molecules, implying that interatomic forces decrease and the state changes from solid to liquid.