[r4bbit_]

Alright, thanks for all of your insights, I will try to think some more.
But, wow, a second carboxyl group on the acid that does not react with NaOH?
I am very very fascinated.

[azmanam]

each drop of my base that is added to the acid, will also react with benzoic acid to produce to make sodium benzoate as opposed to reacting in the neutralization reaction

btw, that is the neutralization reaction - were the original acid benzoic acid.

second carboxyl group on the acid that does not react with NaOH?

Now, I didn't say that.  I said it wasn't a second acid - your unknown is not a diprotic acid...

[r4bbit_]

My best guess so far, diglycolic acid. MW: 134 g/mol exactly twice of the 67 g/mol I got. Has two carboxyl groups in the ends and connected by an oxy in the middle, sort of like an ether. It sorts of fits the premises we laid out, yes, it does have 2 carboxyl groups but once dissolved in water, the ether breaks up into acetic acid and 2-hydroxyethanoic acid or something, but the important thing is, when it dissolves in water, acetic acid is created, therefore it is able to create the nail polish remover smell with the ethanol. As for the pka errors, again, since after it dissolves in water, two separate organic acids are created, it will take twice the amount to neutralize both acids, therefore my volume of NaOH is like a "diprotic" amount because for each mole of NaOH added, two NaOH molecules are required to neutralized both acids. Therefore, if we halve my volume, I should be able to get the correct volume for the "monoprotic" amount.

[Borek]

since only one plateau is present, it showed me that my acid is monoprotic.

Too far fetching. It all depends on the difference between pKas. If the difference is small enough, no plateau separation is observed. See plot for citric acid (triprotic).

[Borek]

O, sodium benzoate. NaOH + Benzoic acid also produces sodium benzoate. Therefore each drop of my base that is added to the acid, will also react with benzoic acid to produce to make sodium benzoate as opposed to reacting in the neutralization reaction, thus I actually have 2 reactions going on at the same time...

Think it over - what is product of benzoic acid NEUTRALIZATION? Write reaction equation.

[azmanam]

once dissolved in water, the ether breaks up into acetic acid and 2-hydroxyethanoic acid

eh.  probably not likely under your reaction conditions.

What are all the functional groups you can think of with a carbonyl group (the C=O double bond).  What are the reactions of those functional groups with NaOH?

[azmanam]

acetic acid ... is able to create the nail polish remover smell with the ethanol.

This is an excellent observation, and one that will be quite useful as we work towards the original acid.  Keep this transformation in mind.

[r4bbit_]

  I am running out of guesses.

[r4bbit_]

From what I know, ketones and aldehydes have carbonyl groups, but I am not sure how they will react with NaOH, (other than neutralization in some of the aldehyde/ketone acids).

[azmanam]

Yeah... you may just end up not having enough information without a bit of intuition.

Let's run with this carbonyl evidence.  You know the compound is a monoprotic acid.  You correctly guessed that the molecule has a second carbonyl group that is not a carboxylic acid.

You know that 2 moles of NaOH react with your molecule - one as a base to remove the acidic proton, one as a nucleophile to chemically alter your compound, and during that same experiment you made this observation:

my values matched acetic acid PERFECTLY

That's an interesting one.  Let's see if we can't integrate that observation in a useful way.  What might that mean about the chemical composition after sodium hydroxide decomp?

The original acid also produces ester w/ ethanol that smells like nail polish remover.  You've already mentioned the reaction for making the nail polish remover smell (acetic acid/ethanol).

Ok, here's what I suggest. Let's start by making a list of functional groups you know that contain carbonyl groups.  Draw out their structures and see if you can't play around with the structures a bit to come up with some molecular fragments that might fit the observational data listed above.

As a matter of curiosity, when you mentioned this:

I actually had the first pink appearing when it was 7 mL or 8 mL, but when i twirled the erlenmeyer, it disappeared.

Can you talk a bit about what the pH was doing at the time?  Did you notice anything qualitative or quantitative here?

[r4bbit_]

Well if the colour of the pink did not stabilize after I twirl, i assume i did not meet equivalence yet 
Carbonyl groups

[r4bbit_]

What kind of reaction did the NaOH have on the carbonyl group?
That's what's troubling me, from what I know about C=O
oxidation/reduction are the only ones I've learned. Otherwise, nucleophillic substitition?
Are there any halogens??

[azmanam]

from what I know about C=O oxidation/reduction are the only ones I've learned.

hmm... that could be a limitation.

Poke around this site a bit, perhaps.  the molecules with carbonyl groups are in the lower right corner.

http://www.cem.msu.edu/~reusch/VirtTxtJml/intro1.htm

You don't have any elemental analysis data or empirical formula data, do you?

[r4bbit_]

=( nope

[r4bbit_]

I did a brief read on acetal formation, I am very clueless now.
What exactly is the reaction?