Why is water a liquid at room temperature and pressure? Please be concise.

1 Answer
Apr 23, 2017

Because water is insufficiently volatile at room temperature and pressure to exist as a gas...........


Was that concise enuff? Well, here, I am going to expand the answer. Water is a highly unusual molecule. It is VERY small, and has very low molecular mass. Nevertheless, it exists as a room temperature liquid. Why? Because hydrogen bonding exists BETWEEN water molecules, and this acts as a potent intermolecular force.

And the propensity for hydrogen bonding results from the polarity of the water molecule, which we could represent as #""^(delta+)H-stackrel(delta-)O-H^(delta+)# - in solution these dipoles align appropriately, and this is a potent intermolecular force.

You should compare the normal boiling of water to that of other small molecules, #HF#, #HCl#, #NH_3#, #CH_4# etc. What do you find?