# chemistry

posted by
**Jeffrey**
.

Could someone help me with this please?

In chemistry, we did a lab in which he put brands of commerical vinegar in a microplate. We put in 10 drops of each vinegar in each plate thinger then we added 1 drop of phenolphthalein and then put in as many drops of NaOH as it took to turn the solution pink.

I need help with this lab question:

1)From the two closest trials, find the average number of drops of NaOH required to titrate each vinegar. Use this average number of drops and the given molarity of the NaOH to calculate the molarity of acetic acid in each of the brands of vinegar. Assuming identical volumes for the drops of vinegar and the drops of NaOH solution, the ratio of reacting volumes in liters is the same as the ratio of reacting volumes in drops.

The average number of drops is 64.5 for one of the brands. I think the equation I should use goes like this:

C1=(C2*V2)/V1

where c=concentration and v=volume and the 1 and 2 are subscripts. 2 is NaOH and I think 1 is the vinegar.

Am I on the right track? Please help!

yes.

molarity vinegar x volume vinegar = molarity NaOH x volume NaOH.

You may have used some unit other than molarity for concentration .

thanks