Table 2. EIS Variables for Mild Steel in 1 M HCl and with Varying Concentrations of DS1, DS2, DS3, and DS4 at 30 °C.

inhibitors	conc. (mM)	Rs (Ω cm2)	Rct (Ω cm2)	n	Yo (μΩ sn cm–2)	Cdl (μF cm–2)	χ2	–α (deg)	–S	% IEEIS
blank	0	3.50 (±0.06)	22.5 (±0.4)	0.873	243.0	113.90	0.17431	41.54	0.64
DS1	0.10	2.18 (±0.02)	114.0 (±0.2)	0.869	213.0	121.61	0.43123			80.26
	0.25	2.61 (±0.01)	245.0 (±0.2)	0.867	168.0	102.98	0.48832			90.81
	0.50	2.15 (±0.02)	265.0 (±0.3)	0.844	148.0	81.34	0.50142			91.51
	0.75	2.27 (±0.02)	313.0 (±0.1)	0.860	170.0	105.45	0.65431			92.81
	1.00	3.18 (±0.03)	736.0 (±0.1)	0.852	120.0	78.72	0.60828	69.49	0.77	96.94
DS2	0.10	1.65 (±0.01)	163.0 (±0.2)	0.877	200.0	123.74	0.53373			86.20
	0.25	2.51 (±0.03)	409.0 (±0.1)	0.864	69.9	39.95	0.42672			94.50
	0.50	2.10 (±0.03)	558.0 (±0.3)	0.858	62.4	35.80	0.74196			95.97
	0.75	2.44 (±0.02)	688.0 (±0.3)	0.838	68.1	37.69	0.63103			96.73
	1.00	3.08 (±0.01)	725.0 (±0.2)	0.816	67.7	34.31	0.49849	66.42	0.69	96.90
DS3	0.10	2.60 (±0.02)	81.0 (±0.4)	0.865	220.0	117.34	0.35852			72.06
	0.25	2.94 (±0.01)	145.0 (±0.6)	0.864	172.0	96.20	0.36617			84.48
	0.50	2.55 (±0.02)	149.0 (±0.2)	0.870	180.0	104.82	0.36722			84.90
	0.75	3.25 (±0.02)	225.0 (±0.2)	0.866	200.0	123.78	0.39842			90.00
	1.00	3.95 (±0.02)	395.0 (±0.3)	0.856	175.0	111.64	0.41334	66.18	0.74	94.30
DS4	0.10	3.16 (±0.04)	35.3 (±0.2)	0.869	269.0	133.31	0.24624			36.26
	0.25	4.22 (±0.04)	47.2 (±0.3)	0.873	210.0	107.33	0.24244			52.33
	0.50	4.18 (±0.04)	52.8 (±0.4)	0.869	205.0	112.03	0.24399			57.39
	0.75	3.78 (±0.02)	88.6 (±0.3)	0.873	173.0	94.21	0.23661			74.60
	1.00	7.38 (±0.01)	90.6 (±0.4)	0.868	144.0	74.44	0.14991	49.54	0.58	75.17