Adsorption and Corrosion Inhibition Characteristics of Some Nicotinamide Derivatives on Mild Steel in Hydrochloric Acid Solution

Table 2

Values of activation parameters for MS in 0.5 M HCl medium in the absence and presence of various concentrations IMN and TMN.

Inhibitor	𝐶	𝐸𝑎	Δ𝐻𝑎	Δ𝐻𝑎=𝐸𝑎−𝑅𝑇	Δ𝑆𝑎
	(ppm)	(kJ mol^−1)	(kJ mol^−1)	(kJ mol^−1)	(J mol^−1 K^−1)
Blank	0	19.0	16.4	16.5	−197.6
IMN	200	22.9	20.2	20.4	−191.3
	300	25.4	22.8	22.9	−184.9
	400	25.9	23.3	23.4	−184.3
	500	26.9	24.2	24.4	−183.2
TMN	200	26.4	23.8	23.92	−183.7
	300	30.8	28.1	28.23	−172.9
	400	32.8	30.2	30.29	−168.2
	500	35.9	33.3	33.38	−162.1