What is the waterproof container for taking samples of ocean water, several usually being lowered open on a line and each being closed at the desired depth by the action
of a falling weight called?

Using an attached stopper and attached calibrated line and (2 pound) weight. Simply lower the bottle to the sample depth. When the trip line is pulled the sample collection bottle will begin to fill, overflowing and flushing more than 5 times.

idk what the options are but

these is a strong electrostatic attraction between the ions hence a lot of energy is needed to overcome this attraction

this is why the boiling points are so high