Kinetics and Mechanism of the Oxidation of Naphthol Green B by Peroxydisulphate Ion in Aqueous Acidic Medium

Table 2

Rate data for the effect of added cations (Ca²⁺ and Mg²⁺) on the rate of reaction of naphthol green B with S₂O₈²⁻ at [NGB³⁻] = 4.0×10⁻⁵ mol dm⁻³, [S₂O₈²⁻] = 5.6×10⁻³ mol dm⁻³, [H⁺] = 1.0×10⁻⁴ mol dm⁻³, 𝐼=0.50 mol dm⁻³, 𝜆=700 nm, and 𝑇 = 23±1°C.

Ion	10^3[ion], mol dm^−3	10^3𝑘1, s^−1	𝑘2, dm^3 mol^−1 s^−1
Ca^2+	1.0	8.25	1.47
	10.0	7.84	1.40
	20.0	7.30	1.30
	60.0	7.05	1.26
	80.0	6.91	1.23
	200.0	5.57	0.99
Mg^2+	1.0	7.42	1.33
	5.0	5.59	1.00
	10.0	4.48	0.80
	20.0	4.11	0.73
	80.0	3.65	0.65
	200.0	2.65	0.47