In which solvent does hydrogen-bonding operate most strongly? #"A. ethyl alcohol; B. methyl alcohol; C. diethyl ether; D. tetrahydrofuran?"#

1 Answer
Dec 31, 2017

Answer:

Well, #B#, #"methyl alcohol....."#

Explanation:

Hydrogen bonding occurs when hydrogen is bound to a strongly ELECTRONEGATIVE element, i.e. nitrogen, fluorine, or oxygen. If you look at the simple hydrides of these elements, #NH_3#, #HF#, #H_2O#, these have impossibly high boiling points given the size of the molecule, and the boiling point are certainly higher than the hydrides of elements LOWER in their Group.

And now compare the boiling point of methyl alcohol, #"b.p."# #=64.7# #""^@C# to that of methane, #"b.p."# #=-164"# #""^@C#. What has methanol got that methane ain't got? The answer is intermolecular hydrogen bonding.

In solution the individual methanol dipoles interact, and in aggregate this constitutes a potent intermolecular force....

#H_3C-stackrel(delta-)O-stackrel(delta+)Hcdotsstackrel(-delta)O(H)CH_3#