Answer is: 2. can dissolve.
Ionic compounds separates into particles (ions) in water because of their ionic bond.
For example sodium chloride is ionic compound and strong electrolyte and dissociates in water on hydrated sodium cations and chlorine anions:
NaCl(aq) → Na⁺(aq) + Cl⁻(aq).
Ionic bond is the electrostatic attraction between oppositely charged ions (cations and anions).
I'm not sure about 2 but in 3 it would float
Answer:
The International Date Line passes through the mid-Pacific Ocean and roughly follows a 180 degrees longitude north-south
line on the Earth. It is located halfway round the world from the prime meridian—the zero degrees longitude established in Greenwich
