Activity Coefficient Of Hydrochloric Acid Research Articles

Study of Activity Coefficient of Hydrochloric Acid in 2-Propanol-Water Mixture by Electromotive Force Measurement Method

This paper is mainly focusing on the determination of mean molal activity coefficient of HCl in aqueous acidic medium. The present investigations have been carried out to determine the activity coefficients of hydrochloric acid in 2-propanol water mixture solutions under various conditions to study the ion solvent interactions in different temperatures. The standard molar potential Em0 of the cell; Pt; H2(g) /HCl(m) x% 2-propanol; Hg2Cl2(S)/Hg have been determined in 10%; 20% and 30% (w/w) of 2-Propanol-water mixture solution at three different temperatures 308K, 313K and 318K and molality ranging from 0.005 to 0.1 mol Kg-1. Eo of the cell can be computed by modified Davies equation as below, where K= 2.3026(RT/F), A΄ = appropriate Debye-Huckel constant and Mean molal activity coefficient, The mean molal activity coefficients of hydrochloric acid in aqua organic media and temperature are also computed. The primary ion-solvent effects and the secondary ion-solvent effects are also reported.

Activity Coefficients of (Hydrogen Chloride + Europium Chloride) (aq) Using Harned's Rule and the Pitzer Formalism

Activity coefficients of HCl in (hydrogen chloride + europium chloride) have been determined at temperatures ranging from 278.15 K to 328.15 K at 5 K intervals and at eight constant total ionic strengths of (0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 1.5, and 2.0) mol kg-1. Experimental cell potentials were obtained using a cell without liquid junction of the type Pt|H2(g, p = 101.325 kPa)|HCl (mA), EuCl3 (mB)|AgCl(s)|Ag(s). The treatment of Harned has been used to describe the mean molal activity coefficient of hydrochloric acid as a function of ionic strength in acid salt mixtures. Results indicate that the quadratic form is sufficient for the full range of YB (the ionic strength fraction of the salt) to 0.9 at all the experimental ionic strengths. The ion-interaction model of Pitzer has also been used to calculate Pitzer's mixing parameters ϑH,Eu and ΨH,Cl,Eu for the system H+ + Eu3+ + Cl- + H2O. The values found, ϑH,Eu = 0.2 ± 0.03 and ΨH,Cl,Eu = 0, were similar to those for other trivalent ions studied previously. The parameters used in this study reproduce the activity coefficients of HCl in the mixtures to within 0.016 over the entire range of ionic strengths and within 0.009 for I > 0.05 mol kg-1 over the entire temperature range.

Treasure of the Past VI: Standard Potential of the Silver-Silver-Chloride Electrode from 0° to 95° C and the Thermodynamic Properties of Dilute Hydrochloric Acid Solutions.

From electromotive-force measurements of the cell without liquid junction: Pt;H2,HCl(m),AgCl;Agthrough the range 0° to 95° C, calculations have been made of (1) the standard potential of the silver–silver-chloride electrode, (2) the activity coefficient of hydrochloric acid in aqueous solutions from m (molality) =0 to m=0.1 and from 0° to 90° C, (3) the relative partial molal heat content of hydrochloric acid, and (4) the relative partial molal heat capacity of hydrochloric acid.The extrapolations were made by the method of least squares with the aid of punch-card techniques. Data from at least 24 cells were analyzed at each temperature, and 81 cells were studied at 25° C. The value of the standard potential was found to be 0.22234 absolute volt at 25° C, and the standard deviation was 0.02 millivolt at 0° C, 0.01 millivolt at 25° C, and 0.09 millivolt at 95° C. The results from 0° to 60° C are compared with earlier determinations of the standard potential and other quantities derived from the electromotive force.

The system HCl+InCl3+H2O from 5 to 55�C: Application of Harned's rule

Electromotive-force measurements of cells containing hydrochloric acid and indium chloride have been made to determine the variation of the log of the activity coefficient of hydrochloric acid with change in the amount of indium chloride in the solution. The simpler Harned equations have been used to fit the data. The quadratic terms in the Harned equations for the activity coefficients of HCl in the salt mixtures are required for a good fit of the 968 experimental emf data points at all the experimental ionic strengths and temperatures. The more convenient Pitzer ion-interaction treatment of the data will be reported in a separate publication which will include the values of the Pitzer parameters for pure InCl3(aq), and mixing parameters for H+−In+3 and H+−In+3−Cl−. A comprehensive investigation on the mixed electrolyte solutions at 11 different constant total ionic strengths ranging from 0.05 to 3.5 mol-kg−1 was made at 11 temperatures from 5 to 55°C using the cell without liquid junction of the type: Pt,H2(g, 1 atm)|HCl(mA)+InCl3(mB)+H2O|AgCl,AG (A).

Activity Coefficients of Hydrochloric Acid in Concentrated Electrolyte Solutions. 1. HCl + NaCl + H2O, HCl + LiCl + H2O, and HCl + BaCl2 + H2O at 298.15 K

Electromotive force (emf) measurements have been made using a Harned cell without a liquid junction of the type Pt, H2(0.1013 25 MPa)|HCl(IA), MeCl(IB)|AgCl,Ag containing mixtures of (i) HCl and NaCl, (ii) HCl and LiCl, and (iii) HCl and BaCl2, at constant total ionic strengths of (4, 5, 6, and 7) mol kg-1 and at a temperature of 298.15 K. From these emf measurements, the mean activity coefficients of hydrochloric acid in ternary solutions of HCl + NaCl + H2O, HCl + LiCl + H2O, and HCl + BaCl2 + H2O have been determined, using the Nernst equation. The Harned equation has been used to fit the mean activity coefficients of hydrochloric acid by a least squares method, and the values of the logarithm of the mean activity coefficient of pure hydrochloric acid, log γA0, and the Harned interaction coefficients, αAB and βAB, together with their standard deviations are obtained. The results show that the measured mean activity coefficients of hydrochloric acid in the ternary solutions studied obey Harned's rule at constant total ionic strengths from (4 to 7) mol kg-1 and at a temperature of 298.15 K.

Activity Coefficients of Hydrochloric Acid in Concentrated Electrolyte Solutions. 2. HCl + BaCl2 + KCl + H2O, HCl + LiCl + KCl + H2O, and HCl + NaCl + KCl + H2O at 298.15 K

Electromotive force have been measured using a Harned cell without a liquid junction of the type Pt,H2(0.101 325MPa)|HCl(IA),MeCl(IB),KCl(IC)|AgCl,Ag with Me = Ba, Li, and Na, respectively, at constant total ionic strengths of (4, 5, 6, and 7) mol kg-1 and at a temperature of 298.15 K. In all the measurements, at each constant total ionic strength, the ionic strength of MeCl (M = Ba, Li, and Na) is taken as 20% of the total ionic strength. From the emf measurements, the mean activity coefficients of hydrochloric acid in quarternary mixtures of HCl + BaCl2 + KCl + H2O, HCl + LiCl + KCl + H2O, and HCl + NaCl + KCl + H2O have been determined by the Nernst equation. It is found that the logarithm of the mean activity coefficient of hydrochloric acid in quarternary mixtures studied in this work varies linearly with the ionic strength of KCl, when the total ionic strength of the mixture and the ionic strength of MeCl (Me = Ba, Li, and Na) are constant. An equation is derived which can be used to adequately desc...

Standard potential of the silver-silver chloride electrode and mean activity coefficient of hydrochloric acid in 10 wt% sucrose/water from 0 to 25°C

As part of a study in which electromotive force (emf) measurements are used to determine thermodynamic properties of sucrose solutions approximating fruit juice, it was necessary to determine the standard potential of the silver-silver chloride electrode in this medium. Emf measurements of cells of the type: Pt; H 2 (g, 1 atm) | HCl (m) in 10 wt% sucrose/H 2O | AgCl; Ag, where molality = 0·005 to 0·05 over the temperature range 0 to 25°C, allowed the calculation of the molal standard potential, E 0 m, of the Ag-AgCl electrode in the dilute sucrose mixture. Values obtained were fitted to an equation second-order in temperature, E 0 m = 0·23162 − 4·9204 × 10 −4t − 3·0500 × 10 −6t 2 (t = temperature (°C), sd = 0·02 mV). The mean activity coefficient of HCl, γ ±, in the sucrose-water mixture can be described within the experimental precision of the data to 0·10 m at 25°C using a simple Debye-Hückel model which incorporates an ion-size parameter of 7·8 Å. The results provide a basis for precision emf measurements in dilute sucrose-water mixtures.

Activity coefficient of hydrochloric acid in HCl/MgCl2 mixtures and HCl/NaCl/MgCl2 mixtures from 5 to 45°C

Magnesium, the dominant bivalent cation in natural seawater, exerts a substantial influence on the patterns of ion interactions in this saline medium. Mean activity coefficients of hydrochloric acid in mixtures of this acid with magnesium chloride at four ionic strengths, namelyI=0.1, 0.3809, 0.6729, and 0.8720 mole-kg−1, were obtained from emf measurements of cells without liquid junction at nine temperatures from 5 to 45°C. The three highest ionic strengths correspond to seawater of salinities 20, 35, and 45‰, respectively. In addition, mixtures of HCl, NaCl, and MgCl2 were studied atI=0.6729, the molal ratio of NaCl to MgCl2 being maintained at 7.202 as in natural seawater. The Harned coefficients α1 2 were found to decrease slowly with increase in temperature. The trace activity coefficient of HCl in solutions of MgCl2 as well as in NaCl MgCl2 mixtures was found to be nearly identical with that measured earlier in synthetic seawater of the same ionic strength but containing NaCl, MgCl2, KCl, and CaCl2.

Standardization of silver-silver chloride electrodes from 0 to 60°C

Reference values of the activity coefficient of hydrochloric acid at intervals of 5°C from 0 to 60°C are proposed. With their use, interlaboratory differences among silver—silver chloride electrodes can be eliminated.

Activity coefficient of hydrochloric acid in the system hydrochloric acid-ammonium chloride-potassium chloride-water at constant total molality 0.5 mol kg-1 at 298.15 K

Activity coefficient of hydrochloric acid in the system hydrochloric acid-ammonium chloride-potassium chloride-water at constant total molality 0.5 mol kg-1 at 298.15 K

Activity coefficient of hydrochloric acid in the system HCl?KCl?H2O at 25�C and lonic strengths from 0.1 to 3 moles-kg?1

The activity coefficient of hydrochloric acid has been determined in HCl−KCl−H2O mixtures at 25°C and for seven values of the ionic strength between 0.1 and 3.0 mole-kg−1, using the cellPt;H2(g, 1atm)\HCl(mA),KClBAgCl;Ag

Activity coefficient of hydrochloric acid in aqueous solutions of sodium chloride

Electromotive-force measurements of the cell $$Pt;H_2 \left( {g,1{\text{ }}atm} \right)|HCl\left( {{\text{m}}_A } \right),NaCl\left( {{\text{m}}_B } \right)|AgCl;Ag$$ have been made at temperatures between 5 and 45°C at values ofm A+m B of 0.1, 0.3809, 0.6729, and 0.8720 mole-kg−1. The activity coefficients of HCl in HCl/NaCl mixtures and the Harned coefficients α12 have been obtained. The change of α12 with total molality is consistent with the existence of binary interactions between H+ and Na+ ions. The linear variation of the relative partial molal heat content with the fraction of NaCl in the mixture suggests that an analog of the Harned rule exists for this thermodynamic quantity.

The activity coefficient of hydrochloric acid in aqueous mixtures with perchloric acid at 298.15 K and ionic strengths 0.1 to 3.0 mol kg −1

E.m.f. measurements are reported of the activity coefficient of HCl in aqueous mixtures with HClO 4 at ionic strengths 0.1, 1.0, and 3.0 mol kg −1 using the cell: Pt, H 2| HCl(m 1), MX(m 2)| AgCl, Ag The results are fitted to the Scatchard equations for aqueous electrolyte mixtures and the dominant ionic interactions specific to this mixture are inferred from the Scatchard mixing parameters. The parameter diagnostic of the Cl −1ClO 4 − interaction has the value 0.064 kg mol −1, indicating moderately strong repulsion between these ions, and it is also necessary to make some allowance for ion-triplet interactions.

Thermodynamics of hydrochloric acid in water + 50 mass per cent of ethylene carbonate from e.m.f. measurements at 293.15 to 328.15 K

Electromotive force measurements of cells of the type: Pt|H 2(g)HCl(m) in H 2 + ethylene carbonate|AgCl|Ag at 8 temperatures from 293.15 to 328.15 K have been used to derive (a) the standard e.m.f. of the cell in water + 50 mass per cent ethylene carbonate, (b) the activity coefficient of hydrochloric acid, (c) the relative partial molar enthalpy and relative partial molar heat capacity of HCl at 298.15 K, and (d) the thermodynamic quantities for the transfer of HCl from the standard state in water to the standard state in water + 50 mass per cent ethylene carbonate. The molality m of the acid ranged from 0.0098 to 0.25 mol kg −1. The standard e.m.f. was determined by an extrapolation method making use of the extended terms of the Debye-Hückel theory.

The activity coefficient of hydrochloric acid in lithium perchlorate solutions at an ionic strength of 3 mol kg −1

E.m.f. measurements of the activity coefficient of HCl in LiClO 4 are reported and discussed in terms of the effects of ionic strength and solution composition. The activity coefficient of HCl at constant ionic strength changes less when LiClO 4 is used as a supporting electrolyte than when NaClO 4 is used. LiClO 4 is preferable to NaClO 4 as a swamping medium for the elimination of unwanted salt effects in the study of protolytic equilibria.

The system H2O?HCl?NH4Cl at 25�C: A study of Harned's rule

Electromotive-force measurements of cells containing hydrochloric acid and ammonium chloride at constant total molality have been used to determine the variation of the logarithm of the activity coefficient of hydrochloric acid with change in the amount of ammonium chloride in the solution. The results are interpreted in the light of the recent work of Pitzer, and it is found that Harned's rule holds for both electrolytes.

Activity coefficients of hydrochloric acid in mixtures with potassium chloride in methanol + water solvents from electromotive force measurements at 298.15 K

E.m.f. measurements of the cell, Pt|H2|HCl(m1), KCl(m2), methanol(X), water|AgCl|Ag, have been made at 298.15 K for solvent compositions X= 0, 10, 30, 40 and 45 %(w/w) of methanol, the total ionic strength of each solution being 1 mol kg–1. The logarithm of the mean ionic molal activity coefficient of hydrochloric acid was found to vary linearly with potassium chloride molality for the systems in which the solvent mixture contained 0, 10 and 30 % methanol. For methanol composition above 30 %, the activity coefficient of the acid was a quadratic function of the salt concentration. Secondary medium effects are discussed in relation to differences in specific ionic interactions for the different electrolyte mixtures in water and in the mixed solvents.

The mean activity coefficient of hydrochloric acid in aqueous lithium chloride solution as a function of temperature and acid molality

By means of high precision e.m.f. measurements in cells without liquid junction the mean activity coefficients of hydrochloric acid γHCl in aqueous LiCl solution have been determined as a function of acid molality over the temperature range 0–60°C. Data processing by suitable smoothing procedures has enabled a further increase in precision and reliability of the γHCl data to be achieved. The values corresponding to virtually zero acid molality and, in addition, data for the apparent ionic diameter of the hydrochloric acid system have been evaluated with the Debye-Hückel equation.

Activity coefficients in sulphuric acid and sulphuric-acid-sodium-sulphate mixtures

Equations are developed that permit the calculation of the mean ionic activity coefficients of H+, H+, SO42− (γ1′ and of H+, HSO4−(γ2′) from the measured practical activity coefficient of sulphuric acid, if α (the fraction of total sulphate as SO42−) and K2 (the second dissociation constant of sulphuric acid) are known. On the assumption that the dependence of γ1′ on the ionic strength is similar to that of the activity coefficient of sodium sulphate, the constants in the equation −log γ2′ = 0·5065 μ12/(1 + Aμ12) + Bμ + Cμ3 have been determined to give agreement with observed isopiestic measurements. K2 was re-evaluated from emf measurements in the literature; K2 = 0·0102 is considered to be the best value. Estimates of α, γ1′, γ2′ and Q (the stoichiometric dissociation quotient for HSO4−) are given for solutions of sulphuric acid and sulphuric-acid-sodium-sulphate mixtures in the ionic strength range 0–4·0. The ionic strength dependence of γ2′ is similar to that of the activity coefficient of hydrochloric acid.

Thermodynamics of hydrochloric acid in 95 volume per cent (92.41 mass per cent) ethanol from e.m.f. measurements at 5 to 50°C

Electromotive-force measurements of cells of the type Pt/H 2/HCl( m) in EtOH + H 2O/ AgCl/Ag at 10 temperatures from 5 to 50 °C have been used to derive (a) the standard e.m.f. of the cell of 92.41 mass per cent ethanol, (b) the activity coefficient of hydrochloric acid, (c) the relative partial molal enthalpy and heat capacity of HCl, and (d) the thermodynamic constants for the transfer of HCl from water to 92.41 mass per cent ethanol. The molality of the acid ranged from 0.0099 to 1.085 mol kg −1. To obtain the standard e.m.f. it was necessary to correct for ion-pair formation and to use the extended terms of the Debye-Hückel theory. The ion-size parameter, chosen to minimize the sum of the squares of the deviations, varied only slightly with temperature, from 3.97 Å at 5 °C to 4.31 Å at 50 °C.