The surface tension of a liquid at its boiling point is what?

[nishant]

the surface tension of a liqud at its boiling point is what?

 

[nishant]

is it zero?

 

[nmondal]

At the boiling point we still have the liquid as well as have the gas/vapour.
So we have 2 different state of the same object.
Naturally then the rules we apply for the liquid applies at that point to...which means, the liquid still has a surface tension, but it is reduced. It does not drops to zero.
To get a feel, think of a better liquid, like mercury!
It is reduced because the same-same bond strength [Non-Techie Version of the Bonding!] reduces while boiling
.

 

[Dr.Brain]

Suppose the Surface Tension Of A Liquid is 'S' in normal conditions. As with increase in temperature some of the atoms escape the liquid surface,surface energy decreases and hence relative forces between the molecules on the surface decreases and hence Sufrace tension decreases.Therefore at Boling point , Surface Tension decreases considerably. Therefore the value is ofcourse not zero but quite less than the normal value and the value varies from liquid to liquid.

 

[nishant]

so it is not so that it cannot be found?

 

[GCT]

Using a pipet, place one drop of room temperature water and one drop of boiling water side by side on a hydrophobic surface

http://hyperphysics.phy-astr.gsu.edu/hbase/surten.html#c3

 

[Dr.Brain]

At Boiling pont:: Surface Tension approaches Zero

At Critical Temperature: Surface Tension is exactly zero

Because at critical temperature the intermolecular forces between liquid and gases balance each other and hence liquid expands without any restriction.