# Thread: Can anyone help me clarify this titration problem?

1. I don't fully understand what I'm supposed to do. I know how to do the calculations, but the concept is what I don't get too much. We discussed standardization in that class. The directions of the assignment is:

Below is assorted data from a theoretical titration that was completed and the possible solutions that were used. There are several titrations that could be theoretically done given the information below. Considering any TWO possible titrations:
1) Given that the indicator used was phenolphthalein which substance was put in the burette and flask
2) Make any relevant calculations.

To sum up the data:
Average volume used in 3 out of 6 trials ( other 3 were irrelevant ) = 12.66mL

These were the acid-base that I found to match up: unknown + known

0.1M Mg(OH)2 + 0.1323M H2SO4
1M HCl + 1.005M KOH
0.1M H2SO4 0.09875M KOH

The volume of the substance in the flask was 10.0mL, and given that the indicator was phenolphthalein, the acid was in the flask.

I calculated that 0.1323M H2SO4 + 0.1M Mg(OH)2 (ignoring the inaccurate molarity) the molarity of the magnesium hydroxide would've been 0.10441M (this is right, according to my teacher).

So that would've been one match up. What's the other match up? I think, because it is standardization, I would have to use the new and more accurate molarity to calculate another match up with the other given unknown (which are both acid)?

Calculating this, I found that 0.1M H2SO4 + 0.10441M Mg(OH)2 to be the closest match at = 0.1318M H2SO4 (under the same volumes as before).

Was I doing it right?

2.

3. Use the same number of s.f. in your calculations?