In my experiment I placed NaCl in glycerin for 10 minutes or more and it did not dissolve. I have looked to see if glycerin is polar or nonpolar and the information uses glycerol and glycerin interchangeably, yet they are not the same. Some information states it is polar and other sites say it is nonpolar. The chemical structure of glycerin has 2 primary and 1 secondary hydroxyl groups. This to me would classify it as polar. What is your opinion? Thanks!!!

From the way this post is worded I'm wondering if this is part of a laboratory experiment as a student OR if this is an uncontrolled exercise on your own? Did you stir to see if solubility was increased? How do you know none dissolved?

First, glycerin and glycerol are the same thing and the names are interchangeable. What makes you think they are different compounds? Second, according to at least three sites I found on the web, NaCl issoluble and that many polar compounds (NaClO4, KCl, etc) are soluble as well. This would indicate some polarity to glycerin although not highly polar. It competes for hydrogen bonding in water.
Here is one web page that gives more information.
http://www.sy-kogyo.co.jp/english/sei/tech_data/phase4.htm

To determine whether glycerin is polar or nonpolar, we need to analyze its chemical structure and the nature of its intermolecular forces.

Glycerin, also known as glycerol, has a chemical formula of C3H8O3. It consists of three carbon (C) atoms, eight hydrogen (H) atoms, and three oxygen (O) atoms. The molecule has two primary hydroxyl groups (-OH) and one secondary hydroxyl group (-OH).

The presence of hydroxyl groups in the chemical structure of glycerin indicates that it can form hydrogen bonds. Hydrogen bonding is a strong intermolecular force that occurs between atoms of highly electronegative elements (such as oxygen) and hydrogen atoms bonded to highly electronegative elements.

Because glycerin can form hydrogen bonds, it suggests that it is a polar molecule. However, to be certain, we can further examine its molecular geometry.

Glycerin has a symmetrical structure, with the hydroxyl groups located in a manner that allows for the formation of hydrogen bonds. This structural arrangement reinforces the polarity of the molecule, as the polar bonds do not cancel each other out due to symmetry.

Based on this information, it can be concluded that glycerin is indeed a polar molecule. The presence of the polar hydroxyl groups and the ability to form hydrogen bonds make glycerin soluble in polar solvents, but less soluble in nonpolar solvents like NaCl. This explains why the NaCl did not dissolve in glycerin.

When researching the polarity of glycerin, it is important to note that the terms glycerin and glycerol are often used interchangeably in scientific literature, as they refer to the same compound. However, some sources may use these terms inconsistently, leading to confusion. In this case, it is helpful to consider the molecular structure and intermolecular forces involved to arrive at a conclusion about glycerin's polarity.