Product Tested: Crest Pro-Health Mouthwash
Predictions/Comments: For anyone who has tried mouthwash, you'd know that they are definitely not sour, but bitter and minty. The bitter taste can already indicate that the mouthwash is a base, although this doesn't apply to all brands.
Method: We poured the mouthwash into the blueberry juice, stirred it thoroughly to see the resulting colour.


Conclusion: With the dark purple colour, as we can see from the above photo, we can confirm that this mouthwash is a base, with an approximate pH of 12. (Check pH circle on the reference widget)