Vapor Pressure

[Ibraiz]

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Which compound has the lowest vapor pressure?
a) 2-pentanone
b) 2-pentanol
c) Pentane
d) Pentanal
e) Hexane

Correct Answer: B
Explanation: A Low Vapor Pressure = High Boiling Point.
Compound with hydrogen bonding such as alcohols show high boiling points and lower vapor pressure.

so the boiling point is when the vapor pressure is equal to the ambient pressure. Thus, with high vapor pressure = high boiling point. Right? I am little confused.

I thought vapor pressure is the pressure exerted by the liquid when heated as a result of increased kinetic energy.

Can someone please provide an explanation for this question please?

 

[JBarr29]

Which compound has the lowest vapor pressure?
a) 2-pentanone
b) 2-pentanol
c) Pentane
d) Pentanal
e) Hexane

Correct Answer: B
Explanation: A Low Vapor Pressure = High Boiling Point.
Compound with hydrogen bonding such as alcohols show high boiling points and lower vapor pressure.

?

the reasoning you have here is correct. simply just ask yourself which of those will have the highest boiling point. The hydrogen bonding in the alcohol is most important factor here, so it will have the highest bp.

also, think of vapor pressure as the pressure of the vapor (evaporate) above the liquid or the solid in a closed container.

 

[Ibraiz]

the reasoning you have here is correct. simply just ask yourself which of those will have the highest boiling point. The hydrogen bonding in the alcohol is most important factor here, so it will have the highest bp.

also, think of vapor pressure as the pressure of the vapor (evaporate) above the liquid or the solid in a closed container.

Yes, compound with the H-Bond will have the highest boiling point but how is that relate to Vapor Pressure because I thought high boiling point = high vapor pressure as the definition of boiling point states that boiling point is when the vapor pressure is equal to the ambient pressure. With that being said, we can say if the vapor pressure is higher that means boiling point is high. And I am confused about this concept when the explanation says High Boiling Point = Low Vapor Pressure

 

[mag7ical]

Vapor pressure is the pressure of a vapor on a liquid. The higher the pressure, the more likely it is that the liquid will vaporize. So higher pressure creates unstable liquids.

Unstable liquids have low boiling points because their bonds are easily broken.

Since alcohols are the most stable due to H-bonding, they would have high boiling points and low vapor pressure.