Which of the following solutions will have the lowest vapor pressure?
Practice Questions
Q1
Which of the following solutions will have the lowest vapor pressure?
0.1 M NaCl
0.1 M KBr
0.1 M MgCl2
0.1 M glucose
Questions & Step-by-Step Solutions
Which of the following solutions will have the lowest vapor pressure?
Correct Answer: MgCl2
Step 1: Understand what vapor pressure is. Vapor pressure is the pressure of a vapor in contact with its liquid or solid form. Lower vapor pressure means fewer molecules are escaping into the vapor phase.
Step 2: Know that when a substance dissolves in a solvent, it breaks into particles called solute particles. More solute particles in a solution lead to a lower vapor pressure.
Step 3: Look at the options given in the question. Identify which substances dissociate into more ions when they dissolve.
Step 4: For example, MgCl2 dissociates into 3 ions: 1 magnesium ion (Mg²⁺) and 2 chloride ions (Cl⁻). This means it creates 3 particles in solution.
Step 5: Compare this with other substances. If another substance dissociates into fewer ions, it will have a higher vapor pressure than MgCl2.
Step 6: Conclude that since MgCl2 produces the most particles, it will have the lowest vapor pressure among the options.
