Buffer Neutralisation Question

[Iota]

I'm trying to determine the (theoretical) end-point for a titration of paracetamol with KOH. So I need to work out the volume of 0.1M KOH required to neutralise 125mg of paracetamol.

 

Information about the practical this is based on:

This 125mg of paracetamol tablet is crushed and dissolved in 100cm3, then 25cm³ of this solution is pipetted into a beaker. Titrate this with 0.1M KOH and find the end point.

 

 

I have a method of doing this but I'm not sure it's correct:

 

0.125g/ 151.09gmol^-1 = 8.27*10^-4 mol paracetamol in 100cm³ solution.

 

8.27*10^-4 mol/ 4 = 2.07*10^-4 mol paracetamol in 25cm³ solution (the 25cm³ pipetted into a beaker).

 

 

We are told that the conc. of KOH is 0.1M.

 

With the information available here I said:

 

0.1M/1000*(x) = 2.07*10^-4 mol

 

I rearranged the above to find 'x', which is the volume of solution required to make the same amount of moles that there are of paracetamol, hence enough to neutralise it:

 

(1000*(2.07*10^-4))/0.1 = x = 2.7cm³ of KOH required.

 

 

 

Is this remotely correct? If not can someone help me out?

 

Thanks in advance.

Edited February 16, 2013 by Iota

[hypervalent_iodine]

I didn't check your math, but the way you've done it looks fine to me.

[Iota]

I've double checked the maths then checked it again, should be all right! Thanks.

[Biofanatic24]

Just went over this problem, and yes everything seems to be correct.