(B) major chemical properties of noble metal is the most important common chemical stability (chemically inert), which is mainly manifested in two aspects - aspects of acid, alkali corrosion and oxidation. A comparison of the corrosion resistance of commonly used chemical reagents is shown in Table 2. Table 2  Comparison of Corrosion Resistance of Precious Metals to Some Chemical Reagents Reagents and conditions Au Ag Pt Pd Rh Ir Os Ru H 2 SO 4 concentrated A B A A A A A HNO 3 0.1mol/L A B A A A A 　 70% A 　 A D A 　 C 　 70%10 0°C A D A D A A D Wang Shui Room temperature D D D D A A D 　 boiled D D D D A A D HCl 36% room temperature A B A A A A A 　 36% boiled A D B B A A C Cl2 dry B 　 B C A A A 　 wet B 　 B D A A C press fittings produces accorindg to park ,connex ,vigea and nibco,Approved watermark Press Fittings，press fittings，vigea press fittings，Nibco press fittings Taizhou Runde Company , https://www.zjbrassfittings.com