Assertion: phosphoric acid | /r/HasProperty | required
Facets:
Source sentences:
text: When a more purified phosphoric acid is required, the solvent extract may be purified in advance using a small amount of calcium-free pure phosphoric acid solution.
text: When a more purified phosphoric acid is required, the solvent extract may be purified in advance using a small amount of calcium-free pure phosphoric acid solution.