Question

all of the following are true about the relationship between salt and fresh water except?
the boiling point of water increases as salinity increases
salt water floats on fresh water
higher salinity has a greater density than lower salinity water
the freezing point of water decreases as salinity increases

Explanation:

• Boiling point elevation: When salt (solute) is added to water (solvent), the boiling point of the solution (salt - water) is higher than that of pure water. So, "The boiling point of water increases as salinity increases" is a true statement.
• Density comparison: Salt - water has a higher density than fresh water. According to Archimedes' principle, an object (or a fluid layer) with a higher density will sink below a fluid layer with a lower density. So, salt - water sinks below fresh water, not floats on it.
• Density - salinity relationship: Salinity is a measure of the amount of dissolved salts in water. As the amount of dissolved salts (salinity) increases, the mass of a given volume of water increases. Since density ($

ho=\frac{m}{V}$) and mass ($m$) are directly proportional (for a constant volume $V$), higher salinity water has a greater density. So, "Higher salinity has a greater density than lower salinity water" is a true statement.

• Freezing point depression: When a solute (salt) is added to a solvent (water), the freezing point of the solution (salt - water) is lower than that of pure water. So, "The freezing point of water decreases as salinity increases" is a true statement.

Answer:

Salt water floats on fresh water