[panic]

Hey everyone.  I'm glad I found this forum, because I'm pretty stumped by this problem. I've been working on this for a long time now, and right now, I just really need your help.
Here goes.

A sample of diprotic acid with a mass of 0.1208 g is titrated with 0.1011 M NaOH, requiring 17.95 mL to reach the end point. Determine the formula mass of this acid.

I'll denote the mystery diprotic acid with H₂A.

Ok, this is the only thing I know. In order to get the 0.1011 M NaOH, the equation must've looked like this, with the missing values in red:

0.1208 g H₂A x     moles H₂A         x   moles NaOH  x   1  = 0.1011M
                          grams H₂A                 moles H₂A       0.01795 L

And so.. I'm stuck.  Please help.
Thanks so much, I appreciate your time.

[Yggdrasil]

Always start with a balanced chemical reaction.  From there you can get one of your missing values.

[panic]

Hey thanks for the quick reply.

Ok, so I could start with:

__H₂A + __NaOH ----> __H₂O + __NaA ?

My biggest problem is I don't know the equation itself, and I can't make up a balanced equation itself. 

Thanks

[Yggdrasil]

That's the equation you should try to balance.

[panic]

Oh yeah.... I get it now..!. 

Thanks so much!