Compounds that contain sulfate groups (  )are soluble in water, unless they are bound to mercury, strontium, lead, calcium, or barium. Hence, barium sulfate, , is insoluble in water.

Compounds that contain nitrates ( ), ammonium (  ), and alkali metals are generally soluble in water. Compounds containing halogens are soluble in water unless they are bound to mercury, lead, or silver.

When  is dissolved in water, it forms  and . Both of these are basic compounds.

Each of the other answer options will result in at least one acidic compound when dissolved in solution.

Since water is polar, it dissolves substances that have electrostatic charge due to electron arrangement. All of the answer choices describe molecules that would have positive and negative components except those with evenly dispersed electrons. This describes a nonpolar molecule, which would not dissolve in water.

Boiling point elevation depends on three variables: the boiling point elevation constant of the solvent, the van't Hoff factor of the solute, and the molality of the solution. In this question, molality is held constant.

First, calculate the van't Hoff for each compound.

Ultimately, we are looking for the greatest product of the boiling point elevation constant and van't Hoff factor (since molality is constant).

Magnesium phosphide has the greater van't Hoff factor and acetic acid has the greater boiling point elevation constant. A solution of magnesium phosphide in acetic acid will thus have the greatest boiling point elevation.

 

We first need to find the boiling point elevation with the equation:

Ammonium phosphate has an van't Hoff value of four; each molecule dissociates into four ions in solution. To calculate the molality, we need to find moles of solute per kilogram of solution.

Next, use the molality, van't Hoff factor, and boiling point elevation constant to solve for the increase in boiling point.

Add this increase to the boiling point of pure water to find the boiling point of the solution.

The local atmospheric pressure at 13,000 feet is less than the pressure at sea level; therefore, it takes less heat to make the vapor pressure meet the local atmospheric pressure. Heat added to the system easily exits again as the water is converted to steam, leaving less heat in the water to cook the food. Food cooks more slowly as a result.

Colligative properties are defined as properties that depend entirely upon the ratio of the number of solute particles to the number of solvent particles. Only osmotic pressure and vapor pressure depression are examples of such phenomena. While color emission is a property of a solution, it depends on the chemical species involved, and not the number of particles.

Based on the equation , we see that there are two factors that differ between the containers and can affect the elevation of the boiling point: molality and the van't Hoff factor ().

The sodium choride added to container 1 has a molality of 2, as well as a van't Hoff factor of 2. As a result, we are looking for a compound that has a larger combination of these two factors, which would cause a higher boiling point. 2m CaF₂ has a molality of 2 and a van't Hoff factor of 3. Since this combination of factors in container 2 would be higher than the combination in container 1, we can conclude that this was the mystery compound added to the container with the higher boiling point.

Note that C₆H₁₂O₆ is the formula for glucose, and will not ionize in solution.

If there is ion pairing taking place in a solution, the van't Hoff factor will be slightly lower than predicted. As a result, the boiling point will not be as elevated as it would be if all of the ions were separated from each other. This conclusion can be draw from the given equation, . The number of particles in the solution does not affect the molality.

In order to answer this problem, consider the equation for boiling point elevation: .

 is a specific constant for the boiling substance, so it will not change between the solutions (they are all aqueous). Molality is designated as "m", and a high molality will result in a higher boiling point, however, the value we want to look at for this problem is , which is also known as the van't Hoff factor. The van't Hoff factor is the number of particles that a single solute will dissociate into when added to a solution. MgCl₂ will dissociate into three particles: 1 Mg²⁺ cation and 2 Cl^- anions. Since 2m of MgCl₂ has the highest molality as well as the largest van't Hoff factor out of the options, it will result in the highest boiling point.