Hi,

Whenever I see something I'm not familiar with, I try to focus on the things I do know and eliminate answers out.

"Which of the following properties is associated with the existence of glycine as a dipolar ion in aqueous solution?"

The answer choices are

A. High dipole moment
B. High molecular weight
C. Low dielectric constant
D. Low solubility in water

Would someone please explain how to approach a question like this where some terminology such as dipolar is foreign? (The correct answer is A)

Here, if I don't know what they mean by dipolar ion, I just try to imagine what glycine will look like in water at pH 7.

It will have a protonated NH3+ and a negative COO- as this is the natural state of these groups on amino acids at pH 7.

Looking at this molecule, you can deduce that A is likely as this separation of formal charge should have a large dipole moment. (this is actually what they mean by dipolar ion in this question)

You can eliminate D because amino acids, being polar are highly soluble in water in general.

You can eliminate C because low dielectric constant is typical of non polar solvents like hexanes, not of water.

You can also eliminate B because glycine is the most low moleculear weight of all the amino acids, and is only a single amino acid - it's very small compared to full proteins and other large biomolecules.

If you can even eliminate a couple of answers for sure in this way, you have a much better statistical chance at guessing answers correctly.

I hope this helps!