Posted by
**Joe** on
.

How do I do this problem?

1. A student did an alkalinity determination correctly, except that the sample titrated had a volume of 90.0 mL. Volume A was found to be 4.50 mL and Volume B was 7.00 mL.

a) Calculate the alkalinity value from these data and then calculate the correct value.

I got this far: A=(2A-B)

A=(2(4.50)-7.00)= 2 mL^-1

Now what do I do?

You say "except that the sample titrated had a volume of 90.0 mL." What should it have been? If you titrated two 90.0 mL samples and found one 4.50 mL to the end point and another 7.00 mL to the end point, just calculate the alkalinity normally. The two won't agree of course, they won't even come close, but that's just poor precision.