The cyclic voltammetry measurement of mercuric chloride HgCl₂ was studied with 0.1M HNO₃ at 289.15 K using a glassy carbon electrode with a different scan rate applied in the medium. The cyclic voltammetry measurement applied against methyl orange dye (M.O.) at 289.15 K with the scan rate effect was studied. The complexation interaction between the mercury ions and M.O. dye occurs by measuring the stability constant and Gibbs free energy. It is seen that Gibbs free energy for molecular interaction between mercuric chloride and methyl orange increases with increased dye concentration and reach -12.1613 Kj/mol using 3.13 × 10-4 M of M.O. dye. In the complexation interaction between mercuric chloride HgCl2 and M.O. dye, there is a decrease in Gibbs free energy and the stability constant with decreasing in the scan rate applied till it becomes -9.052 Kj/mol in the presence of 3.13 × 10-4 M M.O. dye. It is found that there is an increase in Nicholson parameters specific for mercuric chloride with the increase in the concentration of M.O dye that tells the possibility of this medium to work as a leaching solution.