The process of Acid Treatment on gold is very important to do before continuing on gold metal smelting processes, due to deposition of the cementation process is done is still a lot of metal-containing zinc, iron and lead are also entrained. Acid Treatment is a process of dissolution of metals such as zinc, iron and other metal impurities using dilute sulfuric acid (H2SO4).From this process of acid treatment will be easier to concentrate smelting process before the stage of purification to make pure gold, because the metal impurities such as zinc, iron and other impurities that integrates with the content of gold ore has been dissolved by the liquid sulfuric acid (H2SO4). In the use of dilute sulfuric acid (H2SO4) is a blend of metal impurities will easily soluble by dilute sulfuric acid (H2SO4), is a metal that has a positive electrode potential in electrochemical series is rather difficult to dissolve, because the greater the tendency to become ions, and vice versa. A metal with a more negative potential shifts the metal underneath any of the salt solution.
      The same thing applies when reacting sulfuric acid with potassium nitrate. This reaction will produce nitric acid and precipitate potassium bisulfate When combined with sulfuric acid nitric acid behaves as an acid as well as substance to dehydrate, forming nitronium NO2 + ion, which is important in nitration reactions involving electrophilic substitution aroma. Reactions of this type is very important in organic chemistry. Sulfuric acid reacts with most metals via a single replacement reaction, which produces hydrogen gas and metal sulfates. Dilute H2SO4 will attack the iron, aluminum, zinc, manganese, magnesium and nickel, but reactions with tin and copper require hot sulfuric acid and concentrated. Lead and tungsen not react with sulfuric acid. The reaction between sulfuric acid with metals normally would produce hydrogen as shown in the equation below. But the reaction with tin dioxide than will produce hydrogen sulfide.

Fe (s) + H2SO4 (aq) H2 (g) + FeSO4 (aq)

Sn (s) + 2 H2SO4 (aq) SnSO4 (aq) + 2 H2O (l) + SO2 (g)