Free mixing
Free mixing is an interactive experiment in pH & Titration, a free simulation from StudyFi Lab that runs right in your browser.
The beaker holds 50 mL of water with universal indicator. pH = −log[H⁺]: every drop of acid adds H⁺ ions, every drop of NaOH adds OH⁻ ions, which combine with H⁺ to form water. The scale is logarithmic, so ten times more H⁺ moves the pH by only 1. In water [H⁺]·[OH⁻] = 10⁻¹⁴.
Try this: Add one small drop of HCl, then try to get back to exactly pH 7 with drops of NaOH. Why is it so hard?
Frequently asked questions
What does the “Free mixing” experiment show?
The beaker holds 50 mL of water with universal indicator. pH = −log[H⁺]: every drop of acid adds H⁺ ions, every drop of NaOH adds OH⁻ ions, which combine with H⁺ to form water. The scale is logarithmic, so ten times more H⁺ moves the pH by only 1. In water [H⁺]·[OH⁻] = 10⁻¹⁴.
How do I try “Free mixing”?
Add one small drop of HCl, then try to get back to exactly pH 7 with drops of NaOH. Why is it so hard?
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