Question #fa01b

1 Answer
Nov 27, 2016

The acid is "triprotic".

Explanation:

"Moles of NaOH" = 30.5xx10^-3Lxx0.108*mol*L^-1=3.29*mmol.

"Moles of acid" = (0.210*g)/(192*g*mol^-1)=1.10xx10^-3*mol

So clearly the acid is triprotic.

The only acid I know that fits these properties is citric acid, C_6H_8O_7, which is one of the few triacids. I have never titrated this one, but I think you would be hard-pressed to get a phenolpthalein endpoint at the third equivalent.