If the bottle is from glass will burst soon; the plastic container will be melted.
In the first place the water in the bottle would keep the temperature of the plastic down preventing it from burning and leaking, The same as you would do by boiling water over a flame in a paper cup, However the water in the bottle would heat up and eventually the pressure inside the bottle would burst it like a balloon.
bottle whistle
The temperature contrasts would cause differential expansion of the bottle which, being brittle, would cause the glass to crack.
Since air is less dense than water, the air pushes the bottle upward. The water filled bottle would sink because the density is greater than water.
The water in the bottle has room to move when it is half full; it ends up sloshing around trying to remain at its initial position, and much of the energy goes into moving the water instead of the water+bottle.
Yes. You can do this by right-clicking a glass bottle in water or a water-filled cauldron.
If a balloon is filled with water, it becomes less susceptible to being popped over a flame, because the water can absorb some of the heat. Otherwise, the flame will rapidly destroy the material of the balloon (rubber, latex).
hydrogen
The water inside the bottle would freeze.
"The volume of air in the diver decreases."
Nothing. The bottle is now truly empty.
1600