Question

I am doing a home lab experiment about acid-base neutralization. I just need a little help to see if I am doing it correctly.

I completed the experiment and recorded the data.

We were to add 25 ml of vinegar and the 1 ml of cabbage indicator, the add i ml of ammonia at a time to reach a total of 35 ml of ammonia solution.

I observed when approx when 1-2 ml of ammonia was added the solution was neutralized.

Here are the problems I am having:

1. If we were to assume that the vinegar and ammonia reacted in a 1:1 ratio how do the relative concentrations compare?


2. In order to calculate the actual concentration of ammonia what would we require from the neutralized reation?

I think we would need to know the amount of vinegar in mL, and concentration in mols/L as well as pH

3. Could we observe a neutralization by adding vinegar to an ammonia solution?

I think yes because if we add vinegar to the solution it reverses back to pink/red.

Answer 1

A. The data and experimental details are too scant/vague to make sense of the questions.
Your #1. The relative concns can be estimated by the ratio of the volumes used.
Your #2. You would need mL and M of vinegar and mL of ammonia. I don't think the pH of either is needed.

Your #3. No, you can not observe a neutralization between ammonia and acetic acid BECAUSE:
a. ammonia is a weak base.
b. vingar is a weak acid.
c. weak acids titrated against weak bases (or the other way around, too) do NOT have a sharp change in pH at the equivalence point; therefore, the indicator does not have sharp color change. In these titrations, the true equivalence point is never determined.