Using the phase diagram of methane, the pressure and temperature play a critical role in its stability since a slight change in the pressure or temperature will cause a phase change. At low temperature and high pressure, methane hydrate becomes solid (methane hydrate + ice). When the temperature is increased, it becomes liquid. This is one of the main challenges in harvesting methane hydrate, its instability.
It will stay the same. Electric force decreases with distance but increases with magnitude of charge. By doubling them both, they essentially cancel out and nothing changes
