Question

identify the following statements as true or false.
a 2.0% nacl solution has a higher freezing point than pure water. true false
a 2.0% nacl solution has a higher vapor pressure than pure water. true false
a 5.0% nacl solution has a lower freezing point than a 2.0% nacl solution. true false
a 5.0% sucrose solution has a higher boiling point than pure water. true false
a 5.0% sucrose solution has a higher osmotic pressure than a 10% sucrose solution. true false
a 10% nacl solution has a higher boiling point than a 5% nacl solution. true false

Explanation:

Step1: Recall colligative properties

Adding a solute to a solvent lowers the freezing - point. So a 2.0% NaCl solution has a lower freezing point than pure water.

Step2: Recall vapor - pressure lowering

Adding a solute to a solvent lowers the vapor pressure. So a 2.0% NaCl solution has a lower vapor pressure than pure water.

Step3: Consider freezing - point depression

The greater the solute concentration, the lower the freezing point. So a 5.0% NaCl solution has a lower freezing point than a 2.0% NaCl solution.

Step4: Consider boiling - point elevation

Adding a solute to a solvent raises the boiling point. So a 5.0% sucrose solution has a higher boiling point than pure water.

Step5: Consider osmotic pressure

Osmotic pressure is directly proportional to solute concentration. So a 5.0% sucrose solution has a lower osmotic pressure than a 10% sucrose solution.

Step6: Consider boiling - point elevation

The greater the solute concentration, the higher the boiling point. So a 10% NaCl solution has a higher boiling point than a 5% NaCl solution.

Answer:

1. False
2. False
3. True
4. True
5. False
6. True