Assertion: acid | /r/HasProperty | substance
Facets:
Source sentences:
text: Acids are substances that...
text: Acid, any substance that in water solution tastes sour, changes the colour of certain indicators (e.g., reddens blue litmus paper), reacts with some metals (e.g., iron) to liberate hydrogen, reacts with bases to form salts, and promotes certain chemical reactions (acid catalysis).