Aqueous Solutions Of KNO3 Research Articles

Pitzer and Thermodynamic Parameters of Triethanolamine and Glycine in Aqueous Saline Solutions

On the basis of the ionic strength dependence of the equilibrium constant (pK*) of thriethanolamine (TEA) and glycine, the ionic interaction parameters of the species involved in the equilibria TEAH+ ↔ TEA + H+ (for TEA), AH2+ ↔ AH + H+ and AH ↔ A- + H+ (for glycine) in aqueous solutions of KCl and KNO3, respectively, were determined using the Pitzer equations. Values of pK* were expressed on both the molarity and the molality scale at various temperatures and values of thermodynamic quantities ∆G0, ∆H0 and ∆S0 ascertained, for TEA.

Raman and nuclear magnetic resonance studies on the concentration dependence of orientational relaxation times of the nitrate ion in dilute aqueous solution

The perpendicular orientational relaxation time (τ⊥) of the nitrate ion was determined as a function of concentration by the Raman line shape analysis (ν1 stretch) in aqueous LiNO3 and KNO3 solutions in the range of 0.2–1 M and by the nuclear magnetic resonance (NMR) T1 measurement (14N) in MNO3 (M=Li, Na, K, and Cs) solutions in the range of 0.02–1 M; the parallel orientational relaxation time (τ∥) was also determined by the NMR measurement for the solutions enriched in 17O. Both τ⊥ and τ∥ increase linearly with increasing concentration up to 1 M; the limiting values of τ⊥ and τ∥ were 1.25 and 1.9 ps, respectively. The slope increases with the surface charge density of the countercation except for Li+. These trends are predicted in very dilute solutions by the continuum theory developed in the previous paper. The anomalous behavior of Li+ was explained in terms of its strong hydration.

Forces between mica surfaces in aqueous KNO3 solution in the range 10–4–10–1 mol dm–3, showing long-range attraction at high electrolyte concentration

Interactions between mica surfaces immersed in 10–4–10–1 mol dm–3 aqueous KNO3 have been measured: in contrast to earlier studies in this system, at the higher concentration range (> 4 × 10–2mol dm–3) the potential of the diffuse double-layer drops to values ψd < 30 mV. In 0.1 mol dm–3 KNO3 only attraction is observed down to the range of ‘hydration forces’(ca. 2 nm). The discrepancy with the earlier results is attributed to adsorption on the mica of surfactant originating in the Millipore filter used in our previous studies.

Complexation of poly(ethyleneimine) with copper(II) and nickel(II) ions in 0.5 M KNO3 solution

AbstractComplexation of poly(ethyleneimine) (PEI) with copper(II) and nickel(II) ions was studied in a 0.5M aqueous KNO3 solution. The potentiometrically determined logarithm of the three successive formation constants (log kJ) were 8.14, 7.96, and 7.37 for Cu+2‐PEI complexation and 6.74, 6.52, and 6.23 for Ni+2–PEI complexation at 25°C, according to Bjerrum's modified method. The maximum average coordination number was 3.2 for the Cu+2–PEI system and 3.7 for the Ni+2–PEI system. An entropy effect was observed in the third coordination. The wavelengths of maximum absorption of the complexes and the continuous variation method showed that at least two coordination sites of Cu+2 ion and three coordination sites of Ni+2 ion were occupied immediately by PEI as the solutions of PEI and the metal ions were mixed.

Thermodynamic studies on the addition of molecular oxygen to cobalt(II) complexes. Part 3. The cobalt(II)–tetraethylenepenta-amine–O2system in aqueous solution at 25 °C

Calorimetric measurements have been carried out on the heat evolved when O2 is bubbled into KNO3(0.1 mol dm–3) aqueous solutions of Co(NO3)2, tetraethylenepenta-amine (tetren) and HCl, or when a Co(NO3)2 stock solution is added to a KNO3(0.1 mol dm–3) aqueous solution of tetren and HCl under both anaerobic (pN2= 1 atm) or aerobic (pO2= 1 atm) conditions. An acceptable agreement is found between the value for the enthalpy change of formation of [Co2L2O2]4+(L = tetren) when it is obtained through direct measurements of oxygen addition to [CoL]2+ or by using the enthalpy changes relative to the formation of [CoL]2+ and [Co2L2O2]4+ starting from Co2+. The thermodynamic data for the binding of oxygen to complexes of CoII with tetren and other linear polyamines are compared and discussed.

Polarographic Study of Mixed Ligand (o-Mercaptobenzoate–Citrate) Complexes of Cadmium(II), Lead(II), and Thallium(I)

Abstract The mixed ligand complex formation of o-mercaptobenzoic acid and citric acid with Cd(II), Pb(II), and Tl(I) in aqueous KNO3 (μ=1.0 mol dm−3) solutions containing Triton X-100 (0.001%) has been investigated by polarography. It was shown that only one mixed ligand entity MAiXj is formed, where i is two for Cd (II) and one for Tl(I) j is one for all complexes and A and X are the o-mercaptobenzoate and citrate ligands respectively. The stability constants have been evaluated.

Heterogeneous catalysis in solution. Part 23.—Kinetics of a redox system showing complete mass-transport control: the hexacyanoferrate(III)+ iodide reaction at a rotating-platinum-disc catalyst

The rate of the reaction between Fe(CN)3–6 and I– has been measured from 5 to 30 °C in 1 mol dm–3 aqueous KNO3 solution both homogeneously and in the presence of a large anodically preconditioned platinum-disc catalyst rotating from 100 to 2000 rev. min–1. The catalytic rate agreed quantitatively with the mixture current (converted to a rate) at the point where the current–voltage curves of the two separate couples intersected; the mixture potential at this point also agreed well with the potential adopted by the catalysing disc. This confirmed the electrochemical mechanism of the platinum catalysis. That the catalytic process had become wholly mass-transport controlled was shown by the fact that the catalytic rates always varied proportionately with the square root of the angular velocity (ω) of the disc, while the catalyst potential remained independent of ω. Other predictions of the theory in the preceding paper to be fulfilled within experimental error were the kinetic orders of the heterogeneous reaction, the marked changes in these orders on adding the product Fe(CN)4–6 to the initial mixture, and the negative Arrhenius activation energy associated with the catalytic rate constant.

Forces between mica surfaces bearing adsorbed macromolecules in liquid media

The forces between two molecularly smooth curved mica surfaces a distance D apart immersed in a liquid have been measured, both in the absence and in the presence of macromolecules adsorbed from the liquid.The forces between bare mica surfaces in 0.2 mol dm–3 KNO3 aqueous solution are repulsive for D≲ 5 nm and correspond reasonably well to electrostatic double-layer (DLVO) theory. Following adsorption of soluble monomeric collagen onto the surfaces from the solution, repulsion commences at D≲ 600–700 nm and increases monotonically with decreasing D, suggesting that the collagen monomers are adsorbed in an upright configuration normal to each surface.The forces between bare mica surfaces in cyclohexane are monotonically attractive for D≲ 10 nm, and appear to obey a van der Waals-like potential acting across the non-polar medium. Following adsorption of polystyrene (of two molecular weights) onto the mica from the cyclohexane, interactions between the surfaces are found to commence at D≲ 2.5 Rg(unperturbed radius of gyration of the respective polymers) and are initially attractive. For D≲Rg the attraction decreases, and on further reducing D strong repulsion between the surfaces is observed. These results may be understood in terms of the phase equilibrium of the polystyrene–cyclohexane system (which under the experimental conditions is below its critical temperature), and are in good accord with the predictions of a recent theory for interaction between adsorbed polymer layers in a poor solvent.

Aqueous hydroxide ion. Part 2.—Ionic association studies by proton magnetic resonance

Measurements of the proton chemical shift in aqueous solutions of TlOH, TlNO3, KNO3, NaNO3, and LiNO3 are reported. Together with previous measurements on aqueous LiOH solutions, the data are analysed in terms of ionic association in the hydroxide solutions. The values of the ion-pair chemical shifts and the molal ionic shift for the thallous ion are discussed.

Surface tensions of aqueous solutions of some 1:1 electrolytes

Measurements of the surface tension of aqueous solutions of NaF, KF, NaNO3 and KNO3 have been made by means of the ring detachment method. The data were obtained for a range of concentrations and temperatures and analysed using the Gibbs equation. A simple model is proposed which explains the correlation found between the surface-tension data and the standard hydration enthalpies of the salts.

Raman spectral studies of ionic motion and ionic interaction in aqueous nitrate solutions

The Raman spectra of the totally symmetric ν1(A 1′) mode of an NO3 - ion have been recorded in aqueous LiNO3, NaNO3, KNO3 and NH4NO3 solutions at various concentrations. The vibrational and rotational correlation functions have been calculated from the Fourier transform of the Raman profiles. Reorientation of the symmetry axis of an NO3 - ion in the aqueous solutions may be represented by the inertial motion for short times (t ≲ 0·15 ps, jump angle 17°), and by the rotational diffusion for longer times (t ≳ 0·3 ps). An effective moment of inertia for short times has been found to be I ⊥ = 20 × 10-39 g cm2, which suggests, as compared with the free NO3 - value I ⊥ 0 = 6 × 10-39 g cm2, some association with the surrounding water molecules or cations. The mean-square torque acting on an NO3 - ion from the moment analysis has been found to increase linearly with nitrate concentration. The torque on an NO3 - ion in concentrated nitrate solutions is predominantly from other ions, while the contribution from an ...

Relative sound velocities of sea salts at 25°C

The relative sound velocities (u−u0) of aqueous HCL, LiCL, NaF, NaCL, NaBr, NaI, NaNO3, NaOH, NaHCO3, Na2SO4, KF, KCL, KBr, KI, KNO3, K2CO3, K2SO4, RbCl, CsCl, NH4Cl, NH4Br, MgCl2, CaCl2, SrCl2, BaCl2 and MgSO4 solutions were measured from 0.01 to 1.0 at 25°C. The sound velocities were fitted to a function of molality (maximum standard deviation 0.05 m sec−1) u=u0+Am+Bm(3/2)+Cm2, where u0 is the sound velocity in pure water, and A, B, and C are temperature dependent parameters. The adiabatic compressibilities βS were determined from the sound velocities and were used to calculate the adiabatic apparent molal compressibilities φK(S) of the salts. The φK and βS of seawater were estimated by using Young’s rule. The calculated values of φK and βS agree with those determined from the measurements on seawater solution to ±0.18×10−4cm3mol−1bar−1 and ±0.004×10−6bar−1. The sound speeds of seawater calculated from the values of βS estimated from Young’s rule agree on the average to ±0.02m sec−1 (maximum standard deviations 0.07 m sec−1) with the direct measurements of Millero and Kubinski.

Direct measurement of long range forces between two mica surfaces in aqueous KNO3 solutions

WE have constructed an apparatus for measuring the forces between two surfaces immersed in a liquid directly as a function of separation, and report initial results for the forces between two crossed cylindrical sheets of molecularly smooth muscovite mica in aqueous solutions of KNO3.

Diffusivities of H2S, C2H2 and N2O in aqueous electrolyte solutions

AbstractDiffusivities of hydrogen sulphide, nitrous oxide and acetylene were observed for aqueous solutions of KI, NH4NO3, MgCl2, KNO3, CaCl2, Na2SO4, NaCl, NH4Cl and KBr by using the laminar jet. Solubilities used in the calculations of diffusivities were also measured for nitrous oxide and hydrogen sulphide.It is found that diffusivities of these gases show similar behaviour to those of carbon dioxide obtained by Ratcliff and Holdcroft, and Onda et al., and it is possible to estimate accurately diffusivities of these gases in aqueous electrolyte solutions by using the correlation for carbon dioxide proposed by Onda et al. Moreover, the results proposed by Gubbins et al., are also confirmed for more extended systems.

超硬合金の陽極溶解過程について

Electrochemical behaviour of cemented carbide electrode has been experimentally investigated. In this paper some result of experiments are presented with poarization curves of cemented carbide in aqueous solution of potassium and sodium nitrate and anodic process of the materials is discussed. The data were checked by means of potentiostatic method and chemical analysis. Surfaces of the electrode were examined by electron microscopy of replica. The main results obtained are summarized as follows : 1) Characteristic curves of the current-potential in aqueous solution of KNO3 and NaNO3 show the same features. There are four (WC-Co alloy) or five (WC-TiC-Co alloy) distinct stages in the curves according to the anodic reactions.2) In the first stage, it takes place of the dissolution of cobalt in the diralent state as prored by potassium nitrite reaction and deformation of carbide component is observed (the fourth stage) after gas evolution from the solution (the third stage).3) The second stage is a passive stage which indicated by a measurable drop in current. In this stage, current changes exponentially with respect to the time. This may suggest that cobalt oxides are formed on the electrode.4) In the ash grey precipitate of WC-TiC-Co alloy, Ti4+ is detected by hydrogen peroxide reaction. Curve with two maxima for the alloy are obtained and the second maximum (the fifth stage) depend on a rate of potential increasing. The electrode surface is covered with precipitation in the stage.

PCIスタット法によるウラニル塩素イオン錯体ならびにウラニル硝酸イオン錯体の安定度定数の決定

An electrochemical pCl-stat was devised to determine the stability constants of UO2Cl+ and UO2NO3+ ion complexes in the aqueous solutions of KNO3 and NaNO3-NaClO4 containing minor amounts of Cl- ion at 25°C.The stability constant Kc of UO2Cl+ at various ionic strengths μ was estimated from the amount of UO2Cl+ ion obtained by the integration of the current-time curve of the pCl-stat following the additon of a given amount of uranyl salt. As previous investigators have pointed out, the stability constant at higher ionic strengths is relatively small, e.g., Kc=2.42, 1.40 and 0.89 at μ=0.54, 0.82 and 1.06, respectively. However, the thermodynamic stability constant Ka at μ=0 obtained by extrapolation of the curve of Kc against μ, resulted in the remarkably high value of 15.The stability constants of UO2NO3+ were also determined by measuring the Kc values of UO2Cl+ as a function of compositions at constant μ in mixed solutions of NaNO3 and NaClO4. The observed results were 0.37, 0.20 and 0.19 at μ=0.54, 0.82 and 1.06, respectively.