Free Evaporation, Boiling Point and Vapour Pressure MCQs with Answers
107 Evaporation, Boiling Point and Vapour Pressure MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Evaporation is the escape of higher-energy molecules from a liquid surface, while vapour pressure is the pressure exerted by vapour in equilibrium with that liquid. The topic distinguishes evaporation from boiling and relates both to temperature, intermolecular forces, surface area, atmospheric pressure and the boiling point.
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- A. Warmed
- B. Boiled
- C. Frozen
- D. Cooled
Explanation: The liquid is frozen with the help of a freezing mixture and the space above the liquid is evacuated.
Correct answer: Frozen- A. Remains constant
- B. Becomes zero
- C. Decreases
- D. Increases
Explanation: As the temperature of water reaches its boiling point, 100°C, liquid water begins to convert to water vapours.
Correct answer: Remains constant- A. 4.579 torr
- B. 23 torr
- C. 8.1 torr
- D. 17.54 torr
Explanation: The vapor pressure of water at 8 Celsius is a known value of 8.1 torr.
Correct answer: 8.1 torr- A. Melting point
- B. Boiling point
- C. Freezing point
- D. Cooling point
Explanation: Boiling point is the phenomenon in which one mole of a liquid is vaporized.The molar heat of vaporization, also known as the enthalpy of…
Correct answer: Boiling point- A. Melting point
- B. Boiling point
- C. Freezing point
- D. Sublimation point
Explanation: The boiling point is the temperature at which the vapor pressure of a liquid becomes equal to the external pressure or atmospheric…
Correct answer: Boiling point- A. Decrease in external pressure increases the boiling point
- B. Increase in external pressure decreases the boiling point
- C. Increase in external pressure increases the boiling point
- D. None of these options are correct
Explanation: A pressure cooker works on the principle that increasing the external pressure increases the boiling point.The boiling point of a liquid…
Correct answer: Increase in external pressure increases the boiling point47. Which of the following is the correct relationship between boiling point and intermolecular forces?
- A. The boiling point increases if the intermolecular forces increase
- B. The boiling point decreases if the intermolecular forces increase
- C. The boiling point increases if the intermolecular forces decrease
- D. The boiling point is not affected by intermolecular forces
Explanation: More energy is required to overcome the intermolecular forces, if the strength of intermolecular forces increases, hence the boiling point…
Correct answer: The boiling point increases if the intermolecular forces increase- A. Vapour pressure
- B. Evaporation
- C. Freezing
- D. None of these options are correct
Explanation: Evaporation produces cooling as the particles at the surface of the liquid gain energy from the surroundings and change into vapour…
Correct answer: Evaporation- A. 280°C
- B. 150°C
- C. 290°C
- D. 110°C
Explanation: Boiling points of glycerin at 1 atmosphere pressure is 290 degrees.
Correct answer: 290°C- A. Exothermic
- B. Spontaneous
- C. Non-Spontaneous
- D. None of these options are correct
Explanation: A process that can take place by itself under the given set of conditions once it has been initiated, if necessary, is said to be a…
Correct answer: Spontaneous- A. Glycerol
- B. Isopentane
- C. Ethanol
- D. Both Options A and C are correct
Explanation: Due to weaker intermolecular forces, vapor pressure of isopentane is more (580 torr) than glycerol ( 0.00016 torr).
Correct answer: Glycerol- A. 50°C
- B. 100°C
- C. 98°C
- D. 67°C
Explanation: Water boils at 98 °C at Murree Hills due to external pressure of 700 torr.
Correct answer: 98°C- A. Tension
- B. Aqueous tension
- C. Aqueous pressure
- D. All of these
Explanation: Option A: Tension is a force along the length of a medium, especially a force carried by a flexible medium, such as a rope or cable.
Correct answer: Aqueous tension- A. Increases
- B. Decreases
- C. Remains the same
- D. Shows abnormal behavior
Explanation: Halogens are non-polar species, hence London dispersion forces act among them and these forces are directly proportional to molecular…
Correct answer: Increases- A. Boiling point increases if external pressure is increased
- B. Boiling point increases if external pressure decreases
- C. Boiling point is not affected by external pressure
- D. Boiling point decreases if external pressure increased
Explanation: The boiling point is the temperature when the internal/vapor pressure of the liquid becomes equal to the external/atmospheric pressure.
Correct answer: Boiling point increases if external pressure is increased- A. Gasoline
- B. Water
- C. Honey
- D. Ethanol
Explanation: A higher evaporation rate ( higher volatility) means that intermolecular forces are weaker and hence are easily overcome leading to the…
Correct answer: Gasoline- A. Liquid and solid
- B. Liquid and vapour
- C. Liquid, solid and vapour
- D. Liquid, vapour and solid
Explanation: Vapur pressure is the pressure exerted by the vapors in the container when both vapors and the liquid molecules are in an equilibrium…
Correct answer: Liquid and vapour- A. External pressure
- B. Vapour pressure
- C. Amount of liquid
- D. Intermolecular forces
Explanation: The boiling point of a liquid doesn't depend on the amount of liquid or the surface area of a liquid.
Correct answer: Amount of liquid- A. Cold water
- B. Hot water
- C. Both evaporate at the same rate
- D. Both evaporate slowly
Explanation: Hot water evaporates faster than cold water because, at higher temperatures, more molecules are moving faster; therefore, it is more…
Correct answer: Hot water- A. It is higher than the normal boiling point
- B. It is lower than the normal boiling point
- C. It is lower than the freezing point
- D. All of these
Explanation: Option A is correct since a pressure cooker is based on the principle that the boiling point of water increases with the increase in…
Correct answer: It is higher than the normal boiling point