What intermolecular bonding occurs in #"methylated spirits"#?

1 Answer
Jun 9, 2017

Hydrogen bonding and dispersion forces.........

Explanation:

#"Methylated spirits"# is MOSTLY #"ethyl alcohol"#, and is a widely used industrial solvent. A volume of #"methyl alcohol"# or #"phenol"# is added so that if you drink it you will go blind; the methanol denatures the ethyl alcohol; and thus commercial supply escapes the taxes and duties commonly levied upon alcohol. Methylated spirit might be up to 5% methanol by volume.....

And thus the intermolecular forces in metho are basically the same as in ethanol, hydrogen bonding and dispersion forces between the hydrocarbyl chains. To appreciate the relative importance of each interaction it might be instructive to interrogate the normal boiling points of methane versus ethane, and methanol versus ethanol:

#"boiling point:"# #CH_4, -164# #""^@C;# #H_3C-CH_3, -89# #""^@C;# #CH_3OH, 64.7# #""^@C;# #H_3C-CH_2OH, 78.5# #""^@C.# The effect of hydrogen bonding as an intermolecular force is well-illustrated.