This product of the Ostwald Process combines with hydrochloric acid to form aqua regia.
The purex process begins by dissolving used nuclear fuel in an aqueous solution of this compound.  Heating a mixture of Gunzburg's reagent and this compound gives a yellowish-red residue, while Erdmann's reagent combines it with (*) sulfuric acid. A 90% platinum/10% rhodium gauze catalyst is the most common one used in the first step of the process that produces this compound, which consists of three oxidation steps and is named after a German chemist born in Latvia.  This product of the Ostwald Process combines with hydrochloric acid to form aqua regia. For 10 points, identify this strong acid used in the production of fertilizers and other nitro compounds.
The purex process begins by dissolving used nuclear fuel in an aqueous solution of this compound.  
{nitric} acid [accept {HNO3}; accept {aqua fortis}] (1) [DW]