Question

Question #e9497

Answer 1

I assume you mean when compared with water.

Indeed, a stream of ethanol is deflected slightly less than a stream of water because ethanol has a smaller net dipole moment than water.

A net dipole moment is a measure of how polar, or nonpolar for that matter, a molecule is. In other words, for a polar molecule, a net dipole moment expresses the magnitude of the difference between the partial positive part of the molecule and the partial negative part of the molecule.

![www.cavemanchemistry.com]()

The bigger the net dipole moment, the more polar a molecule will be. The more polar a molecule is, the more it'll be attracted to the charged particles in the rod.

![http://skullsinthestars.com/2011/05/27/water-has-properties-that-are-positively-electrifying/]()

Check out video of a stream of water being bent - a plastic ruler is used in the demo. The stream of water bends due to the polarity of water molecules.

Video from: Noel Pauller

The partial negative part of the ethanol molecule, i.e. the oxygen from the `"-OH"` group, will be attracted to the positively charged particles in the rod, causing the stream to be deflected.

However, because ethanol has a smaller dipole moment than water - approximately 1.68-1.69 D, compared with 1.85-1.87 D for water, this deflection will not be as significant as the deflection of a water stream.

This happens of course because the charge separation in the ethanol molecule is smaller than the charge separation in the water molecule `->` the attraction to the positively charged particles in the rod will be weaker.