To extract gold from its ore, the ore is treated with sodium cyanide solution in the presence of oxygen and
water.
4Au(s) + 8NaCN(aq) + O2(g) + 2H2O(1) ►
4NaAu(CN)2(aq) + 4NaOH(aq)
a. Determine the mass of gold that can be extracted if
25.0 g sodium cyanide is used.
b. If the mass of the ore from which the gold was
extracted is 150.0 g, what percentage of the ore is
gold?

According to arrhenius theory of acid and bases, an acid is a proton donor, while base donates hydroxyl ions. further, acid and base reacts to form salt and water.consider following example.hcl    +      h2o          →      cl-          +      h3o+here, hcl has donated a proton, hence it is an acid.now consider following reactionhcl      +      naoh            ↔      nacl      +        h2oin this reaction, hcl donates proton, hence it is acid. on other hand, naoh donates hydroxyl ion (i.e. hence it is a base.