... brownish black powder,insoluble in water And ethanol, soluble in acid, liquid ammonium chloride andpotassium cyanide.Usage: Mainly applies ... 4, dielectric constant 18.10, insoluble in water, soluble in acid, ammonia, ammonium chloride, dissolved in sodium hydroxide ... be reduced to metallic copper. ItemStandard IStandard IICuO , % ≥9998Muriatic acid insoluble substance ≤ ,%0.050.20Cl , % ≤0.020.20SO 4 ...