I was working on this science project.

I was on step 11, day. 4. Since day 2, I found out that my pH and the mass of the rock (limestone) stopped changing. This project should proves acidic water makes rocks disappear.

I think I did something wrong. Did I?

  • $\begingroup$ Sorry, you need to edit this question substantially to prevent it from getting closed as unclear what you're asking. Describe the experiment here so that we don't have to go elsewhere to find out what you're talking about. Also, no, we can't see, I was on step 11, day. 4. Describe that step, why its is important, what you did, what did not work. $\endgroup$
    – Jan Doggen
    Apr 15, 2019 at 7:25
  • 1
    $\begingroup$ please take a look at what happens when you add an alcaline rock to an acidic solution,does it get more acidic or less acidic. $\endgroup$ Apr 15, 2019 at 8:19

1 Answer 1


First of all, the rocks do not disappear they dissolve, so they are still there only dissolved into the liquid.

You are using an acid (vinegar), this has a low pH.

The rocks you are using (limestone) they have a high pH (alkaline).

The alkaline rock you add to the acid will dissolve but only until the acid is neutralized. The reaction stops when the pH reaches close to 7,0.

If you had used less limestone or more vinegar the rock will be fully dissolved but the pH of the liquid will stay low. To neutralize the vinegar you must then add more limestone.

So you did nothing wrong except maybe using too little acid.

I will stop my answer here, but if you had taken this reaction one step further you would have made marble (the bubbling you might have seen was carbon dioxide CO2).

  • $\begingroup$ @fred thank you for the edit. $\endgroup$ Apr 16, 2019 at 16:41
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    $\begingroup$ @trond_hansen: glad I could help, fellow cat guardian. $\endgroup$
    – Fred
    Apr 16, 2019 at 16:52
  • $\begingroup$ @trond_hansen: Thanks for answering the question! I've been stuck for five days. And fred of corse. $\endgroup$
    – Dylan
    Apr 20, 2019 at 15:59

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