The bubbles indicate that there is a gas dissolved in the liquid, which may remain dissolved when the liquid is very cold, inside the refrigerator.
When the temperature of the liquid increases, it reduces its ability to dissolve the gas and the gas escapes (bubbles) from the liquid.
At the end, the behavior of the liquid permits you to conclude that the liquid is a mixture because it has a gas dissolved in it.
Salt dissolved in water is a solution, therefore
- salt is not chemically bonded to water
- the ratio of salt to water may vary
- salt and water retain their own chemical properties
<u>Explanation:</u>
Salt (sodium chloride) is formed from positive sodium ions bonded to negative chloride ions. Water can dissolve salt because the positive part of water particles attracts the negative chloride ions of salt. The water particle effects to be charged negatively near the atom of oxygen and positively near the atom of hydrogen.
Since contrasts attract, the water molecules tend to join collectively like magnets. Water is called the universal solvent since it can solve more substances than any other liquid. The salt and water retain their unique chemical properties.
