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A new Coumarine derivatives azo dye; 8-(3-phenyl-5-pyrazolylazo)-7-Hydroxy-4-Methyl Coumarine were synthesized. The effect of pH on the spectra of the synthesized ligand, the chromogenic reaction and the stability constant of Co+ 2, Cu+ 2, Ni+ 2, and Zn+ 2 ion complexes with the synthesized ligand were studied and determined conductmetrically and spectrophotometrically. The optimum pH was determined for the complexes. 1:1and 2:1(L:M) stoichiometric complexes has been formed in solutions. The order of the stability constants of the complexes under study was; Co+ 2+ 2< Cu+ 2. These metal ions were determined using the ligand as indicator. The ligand can be used as acid-base indicator. The ability of controlling corrosion of carbon steel in 1M of acidic solution of hydrochloric was electrochemically proven at room temperature. The inhibition indicated with different tests including Open circuit potential (OCP), Potentiodynamic Polarization (PP) and Electrochemical Impedance Spectroscopy (EIS) tests. The adsorption of inhibitor indicated from PP test followed Longmuir isotherm. Adsorption constant and Gibbs free energy were also calculated and explained.

imple and sensitive spectrophotometric determination method of trace amounts of silver(I) ion using 2-(4-nitro-benzaldehyde)-benzimidazole-hydrazone has been devised. Silver(I) react rapidly with this reagent and forms a red stable chelate, in weak acid medium, which obeys Beer’s law at 496 nm with a molar absorptivity 6.9 ⋅ 103 l mol cm-1 and Sandll’s sensitivity 1.56 ⋅ 10− 3 µg cm-3. The stoichiometry and stability constant of silver chelate has determined using spectrophotometric, potentionmetric and conductometric methods. Interferences from various foreign ions were studied. The nature of the solid chelate has also studied.

The inhibiting effect of the expired meloxicam on the corrosion of mild steel (MS) in 1 M HCl was tested by the weight loss, electrochemical frequency modulation, potentiodynamic polarization (PP) and electrochemical impedance spectroscopy techniques. The PP curves showed that this drug acts as mixed type inhibitor. This drug was adsorbed chemically on the MS surface following the Temkin adsorption isotherm. Some thermodynamic parameters were computed and discussed. The results indicated that the protection efficiency increases by raising both the doses of the inhibitor and the temperature of the medium. The morphology of the MS surface was analyzed by scanning electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy. All of the obtained results from different techniques are similar.

In this study, the inhibition effect of Tamarix Boveana (TB) extract on Cu corrosion in 1 mol L–1 (HNO3 + H3PO4) mixture was studied. Electrochemical techniques such as (potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM)) and non-electrochemical technique such as mass loss were used. Results showed that TB extract has good inhibition efficiency (IE), follows Langmuir adsorption isotherm and all of the methods are in good agreement. The IE increased by increasing the concentration of the extract and decreased by increasing the temperature so, the extract adsorbed on Cu surface physically. The IE depends on the concentration of the extract and reaches 73.5% at 300 ppm of the extract. PP results revealed that the (TB) extract doings as mixed type one. Surface analysis revealed that the extract components are adsorbed on Cu surface forming a film.

The corrosion performance of α-brass in 1 M HNO3 and in the presence of polyethylene glycol (PEG) has been investigated using AC impedance spectra (EIS), potentiodynamic polarization (PP), electrochemical frequency modulation (EFM), and mass reduction (MR) techniques. The outcome data of EIS showed a rise in the resistance charge transfer (Rct) and a decrease in the capacitance double layer (Cdl). Protection efficiency (IE) of PEG has been obtained by varying the dose of the PEG and temperature. PEG adsorbed on α-brass in acidic solution follows isotherm Langmuir. The polarization curves displayed that PEG acts as a mixed-kind inhibitor. The parameters obtained from thermodynamic activation of corrosion α-brass in 1 M HNO3 were obtained and debated. The results obtained from all tests were in excellent agreement.

The electronic absorption spectra of [3-(2-thenoyl) 3-(p-NO2-phenylhydrazone) ethyl pyruvate] (I), p-Br (II) and p-CH3 (III) were studied in ethanol and the spectra comprise four absorption bands which assigned to the corresponding electronic transition. The pK values of these compounds have been determined spectrophotometrically and pH-metrically, the results shown that the interval range for color change of compound (I) is (8-10) similar to that of phenolphethalin indicator, indicating that this compound can be used as acid-base indicator. The successive stability constants of the compounds under study with some transition elements (Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO2(II), La(III) and Zr(IV) have been determined pH- metrically. Stoichiometric complexes with ratios 1:1 and 1:2 (M: L) were formed for all metals. The pK of the three derivatives and the values of the stability constant (logK) of the complexes have the order; III > II > I. Also conductometric titrations have been carried out and the results show that this titration can be used for determination of both the metal ion and the ligand concentrations by each others.