I am an AP aramuseum.org student and also there is a tiny detail worrying polarity of molecules that ns am perplexed about.

My review publication (Princeton review) claims that ethanol has actually stronger intermolecular pressures than methanol since it has a big molecular mass and is therefore an ext polarizable and an ext soluble in water 보다 methanol.

You are watching: Is methanol more polar than water

Yet, my aramuseum.org textbook states that both ethanol and methanol space miscible in water, but the more the carbon chain increases, the less miscible that becomes. Further supporting this declare is the fact that methanol is less soluble in hexane, a nonpolar substance, 보다 ethanol. Thus ethanol is much less polar. Plus, heptanol is hardly soluble in water, but according come the Princeton Review\"s logic, it should be even much more soluble in water 보다 methanol since it has actually a bigger molecular mass.

So, which is it? does the enhancement of CH3s make a molecule much more or less polar, and much more or less miscible in water?


alcohols polarity immiscibility
re-superstructure
improve this question
monitor
asked Feb 22 \"17 at 19:35
\"*\"

JessJess
9111 yellow badge11 silver badge55 bronze badges
$\\endgroup$
add a comment |

2 answers 2


active earliest Votes
7
$\\begingroup$
If your publication says exactly that, then it says nonsense. Sure enough, the enhancement of CH2\"s renders a molecule less polar. As for the solubility in water, methanol is miscible - i.e., infinitely well dissolve in it. Therefore is ethanol. How would you to compare the two infinities?

That gift said, the bigger molecule that ethanol is indeed more polarizable (not much more polar, mind you!), and also has much more intermolecular interaction per molecule 보다 methanol, i m sorry accounts for the greater boiling point.


re-superstructure
improve this prize
follow
answered Feb 22 \"17 in ~ 20:21
\"*\"

Ivan NeretinIvan Neretin
29k33 yellow badges6464 silver badges111111 bronze badges
$\\endgroup$
3
include a comment |
6
$\\begingroup$
mine review publication (Princeton review) says that ethanol has stronger intermolecular forces than methanol since it has actually a large molecular mass and also is therefore an ext polarizable

True

Ethanol does top top a molecule through molecule basis have stronger intermolecular forces in between itself and water 보다 methanol and water.

and much more soluble in water 보다 methanol.

See more: How To Convince Your Parents To Get A Ps4 / Xbox One, How Do I Convince My Parents To Buy Me A Ps4

False

Yet, my aramuseum.org textbook claims that both ethanol and also methanol room miscible in water, but the much more the carbon chain increases, the less miscible that becomes.

True

Why?

As you boost the number of carbon-chain linkages the polarizibility of the molecules does in reality increase.

However, the thing that makes tiny chain alcohols soluble in water is not the truth that you have the right to induce a non-polar link to have a quick lived neighborhood dipole (van der Waals forces), but since of the long-term dipole the the alcohol group. The hydrogen ~ above a alcohol (or water) is very positive and the oxygen is an extremely negative, for this reason they entice other polar groups roughly them in a fairly well ordered manner. For brief chain alcohols the alcohols at the finish of the chain can take the ar of the oxygen and also hydrogen on various other water molecules and also with the entropy inherent with mixing deserve to be miscible with water.

For long chain alcohols the non-polar chains deserve to be polarized, but they perform not connect with water almost as strong as other waters and the entropy innate with mixing is not sufficient to offset the energy difference. And also so if there are any other waters \"nearby\" the water molecules will self-segregate, as water is much more attracted to other waters 보다 to the non-polar chains the they room inducing into creating dipoles.

As you add more alkane linkages the molecule becomes much less polar but an ext polarizible - yet this does not include much (comparatively) to the solubility that a non-polar molecule in a really polar solvent choose water contrasted to extremely polar groups.