Cyanide solutions used for heap leaching are made up of sodium cyanide (NaCN). The sodium cyanide solution ([NaCN]-total = 0.01 M) is kept at pH 10.4. The pH is kept high to keep the cyanide in the CN- form. If CN protonates by the reverse of the HCN dissociation reaction,
HCN = H+ + CN- pKa = 9.24
and forms HCN, it will volatilize, and if it volatilizes, HCN can poison mine workers. At pH 10.4, what fraction of the cyanide is in the CN- form?
Calculate the fraction as [CN-] / [NaCN]-total.