Electrochemical kinetic parameters obtained from the EIS technique for the corrosion of C-steel in 1 M HCl without and with various concentrations of investigated compounds at 25 °C.

C.	Conc., M	R p, Ω cm2	C dl, μF cm−2	θ	% IE
	Blank	77.72	105.25 ± 1.731
H1	1 × 10−6	147.2	94.76 ± 1.734	0.472	47.2
	2 × 10−6	164.5	89.91 ± 1.742	0.528	52.8
	5 × 10−6	282.8	55.65 ± 2.333	0.725	72.5
	10 × 10−6	316.9	53.40 ± 2.603	0.755	75.47
	15 × 10−6	338.5	52.17 ± 2.309	0.770	77.0
	20 × 10−6	654	42.98 ± 1.201	0.881	88.1
H2	1 × 10−6	143.2	88.59 ± 1.452	0.457	45.7
	2 × 10−6	155.7	85.05 ± 1.732	0.501	50.1
	5 × 10−6	155.7	74.28 ± 2.024	0.501	50.1
	10 × 10−6	155.9	69.95 ± 2.021	0.502	50.2
	15 × 10−6	298.8	64.75 ± 2.022	0.740	74.0
	20 × 10−6	354.3	51.20 ± 1.732	0.781	78.1
H3	1 × 10−6	123.1	79.40 ± 2.027	0.369	36.9
	2 × 10−6	148.2	72.31 ± 2.33	0.476	47.6
	5 × 10−6	286.3	56.45 ± 2.34	0.729	72.9
	10 × 10−6	317.1	51.22 ± 1.45	0.755	75.5
	15 × 10−6	338.5	48.11 ± 2.027	0.770	77.0
	20 × 10−6	653.1	43.19 ± 3.179	0.881	88.1