[spunkylulu]

Can someone tell me if I did this correctly?

"A 0.210-g sample of an acid (molar mass = 192 g/mol) is titrated with 27.1 mL of 0.122 M NaOH to a
phenolphthalein endpoint. The formula of the acid is:"

We have 0.0033 moles of NaOH used and 0.00101 moles of the unknown acid.  Therefore the formula of the acid must be H₃A given that the reaction is

H₃A +NaOH --> NaA + 2H₂O

Did I do this problem correctly?

[Borek]

Looks OK to me.

Actually 192 g/mol is a molar mass of a common triprotic acid that you most likely heard of.