Assertion: grape's skin | /r/HasProperty | dipped in hcl
Facets:
Source sentences:
text: When goldbeater's skin or ox skin is dipped in HCl, rinsed in water, soaked in the tannin solution for 5 minutes, washed in water, and then treated with 1% FeSO 4 solution, it gives a blue black color if tannin was present.[citation needed]