Diffusion Of HCl Research Articles

A liquid-phase diffusion experiment

Substituting liquid-phase diffusion of various aqueous ions for classic gas-phase diffusion of HCL and NH4Cl to illustrate Graham's Law of Diffusion; sample data and analysis included.

Diffusion and solubility of HCl in ice: preliminary results

The diffusion and solubility of HCl in ice have been measured between −5 and −15°C by exposing large single crystals of ice to low vapor pressures of HCl for several days. The solubility is found to be (1.0±0.15) × 10−4 mol/1 at −15°C under a 5.6×10−4 Pa HCl partial pressure. The diffusion coefficient is of the order of 10−12 cm2s−1 at −8°C, but the determination of the value is affected by small angle boundaries, where HCl motion is much faster. Extrapolation of these results suggests that HCl is not incorporated into stratospheric ice crystals.

Gastric damage caused by acidified ethanol: role of molecular HCl

This study was undertaken to test the hypothesis that an increase in the concentration of molecular HCl in ethanolic solutions is at least partly responsible for the severity of damage seen with acidified ethanol. To accomplish this goal, we studied the synergistic relationship of HCl and ethanol by holding ethanol constant at 50% (vol/vol) and varying the acid concentration. In another experiment, acid concentration was held constant at 150 mM HCl, and the percentage of ethanol was varied. Our hypothesis was also tested by substituting sulfate for chloride to form H2SO4, a nonpermeant molecular acid. Results of our studies clearly showed that substitution of sulfate for chloride greatly reduced gastric damage, supporting the hypothesis that diffusion of molecular HCl is contributing to the damage by acidifying cells. In all cases, acidified ethanol solutions using HCl were more damaging than the individual components alone, and the severity of the damage caused by 50% ethanol was noted to be dependent on the concentration of HCl. We therefore conclude that the severity of acidified ethanol damage is dependent on cellular acidification caused by diffusion of molecular HCl.

Diffusion and location of hydrochloric acid in ice: Implications for polar stratospheric clouds and ozone depletion

We have carried out experiments to study the incorporation and movement of HCl within the structure of ice. These involved freezing HCl solutions, and observing them in a scanning electron microscope fitted with an X‐ray microanalysis system. We are able to show that HCl is not easily incorporated into ice crystals, but is strongly partitioned towards the grain boundaries. Furthermore, the diffusion of HCl through ice crystals is slow. These results contradict the interpretation of earlier experiments. They mean that if HCl is to be available for reaction on polar stratospheric cloud particles, as required by current theories of Antarctic ozone depletion, then it must be present in some form other than a solid solution.

Conductimetric measurement of ionic diffusion in porous media. Aqueous HCl, HNO3 and H2SO4 in cation exchange columns

A conductimetric technique is used to determine the diffusion coefficients of electrolytes in porous media. An initial concentration gradient is formed by introducing electrolyte into the lower end of a short column of porous material. The rate at which diffusion spreads the electrolyte along the column is followed by measuring changes in electrical conductance at levels 16 and l56 of the column heights, as in Harned restricted diffusion cells. Binary interdiffusion coefficients are reported for aqueous HCl, HNO3 and H2SO4 at 25°C in columns of Amberlite IR-120(H) polystyrenesulfonic acid cation exchange resin beads. Supplementary data for diffusion of aqueous HCl in columns of glass beads and for aqueous HNO3 in bulk solution are also reported.

Coupled transport of iodide ions during interdiffusion of aqueous HCl and NaOH

Stokes diaphragm cells have been used to study multicomponent diffusion in aqueous HCl–NaOH–NaI mixtures at 25 °C. The nine quaternary diffusion coefficients for the mixture containing 0.025 mol L−1 of each electrolyte are reported. The measured coefficients are used to analyze coupled transport of iodide ions generated by interdiffusion of aqueous HCl and NaOH. The analysis shows that the gradient in concentration of NaOH is twice as effective at producing flow of iodide ions relative to the HCl gradient, and that the NaI gradient substantially alters the rates of diffusion of HCl and NaOH components. Equations are developed for predicting multicomponent transport coefficients that describe coupled transport of ions driven by interdiffusion of strong acids and bases.

ChemInform Abstract: Countercurrent Diffusion of AgNO3 and HCl in Cellulose and Nafion Films results in the deposition of AgCl interlayers.

Chemischer InformationsdienstVolume 17, Issue 40 Physical Inorganic Chemistry ChemInform Abstract: Countercurrent Diffusion of AgNO3 and HCl in Cellulose and Nafion Films results in the deposition of AgCl interlayers. L. E. MANRING, L. E. MANRINGSearch for more papers by this authorS. MAZUR, S. MAZURSearch for more papers by this author L. E. MANRING, L. E. MANRINGSearch for more papers by this authorS. MAZUR, S. MAZURSearch for more papers by this author First published: October 7, 1986 https://doi.org/10.1002/chin.198640008AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume17, Issue40October 7, 1986 RelatedInformation

Approach of the interplay between kinetics and diffusion in hot wall reactors used in V.P.E. of III–V compounds

The diffusion of species diluted in a carrier gas is determined by considering a parabolic profile of the gas velocity over the substrate. The coefficients of mass transport of III–V compounds in the chloride and hydride methods are computed. The diffusion of HCl appears as having an effect at low supersaturation, while the diffusion of GaCl, InCl, As 4 and P 4 molecules decreases the growth rate at high supersaturation. For input values of about 10 −3 atm., the resulting variations of partial pressures change the growth rate of about 10% at 10 μm h −1 for HCl and at 30–40 μm h −1 for GaCl and As 4.

The Linear Response Theory of Mutual Diffusion of HCl in Aqueous Systems

The Linear Response Theory of Mutual Diffusion of HCl in Aqueous Systems

Transport of protons and hydrochloric acid through lipid bilayer membranes

Transport of protons and hydrochloric acid through lipid bilayer membranes was studied by a combination of electrical conductance and pH electrode techniques. In the presence of large pH gradients, proton transport occurs primarily by diffusion of molecular HCl. The permeability of egg phosphatidylcholine/decane bilayers to HCl is about 3 cm · s −1, seven to nine orders of magnitude higher than the permeability to H +, OH − or Cl −. The HCl permeability of phosphatidylserine or egg phosphatidylcholine/cholesterol (1 : 1) bilayers is about 50% lower than the permeability of egg phosphatidylcholine bilayers. Diffusion of molecular HCl may be an important process in tissues exposed to high HCl concentrations, e.g., gastric mucosa. However, at neutral pH the diffusion of molecular HCl is too slow to contribute significantly to net movements of H + or Cl −.

Diffusion of H36Cl in decalcified ivory dentine.

The diffusion coefficient for diffusion of HCl in the organic matrix of elephant's ivory dentine was determined for various concentrations by measuring the fractional uptake of H36Cl in decalcified, cylindrical specimens with concealed end surfaces using a Geiger-Müller counter. Values for the effective diffusion coefficient for sorption of HCl were greatly dependent on concentration (6.1 x l0–6 cm2/sec for 1.0 N HCl to 0.l8-10–6 cm2/sec for 0.01 N). On the basis of an approximate kinetic model the diffusion coefficient for simple diffusion was estimated (9-12 x 10–6 cm2/sec). The effect of stirring on the rate of sorption was negligible.

Gas phase etching of silicon with HCl

An investigation has been made on the etch rate as a function of temperature of (111) oriented silicon by HCl using three independent measuring techniques. At all temperatures investigated a transition from a structureless smooth to a pitted surface occurs with increasing HCl pressure. This pitted surface structure causes irregularities when thickness measurements are performed with a mechanical probe or when interference methods are used. It is shown that a modified weighing technique gives the most reliable results in this pitted region. The temperature dependence of the etch rate is shown to be nearly zero in the temperature range investigated (1350–1500 °K) and for HCl pressures ranging from 0.01 to 0.1 atm. For low HCl pressures this temperature independence is associated with the reaction enthalpy of the reaction Si + 2HCl ⇌ SiCl 2 + H 2 for which ▿ H = +4.5 kcal/mole at 1500 °K. At high HCl concentrations the diffusion of HCl towards the silicon surface is rate limiting and the observed temperature independence is associated with the diffusion constant of HCl which varies only slowly with temperature.

The rate of chlorination of metals and oxides: part III. the rate of chlorination of fe2O3 and NiO in Cl2 and HCL

The rate of chlorination of Fe2O3, NiO, and NiFe2O4 by Cl2 (1073 to 1473 K) and by HCl (1073 to 1273 K) diluted with He or Ar has been measured. The rates were measured as a function of particle size, temperature, gas composition and internal surface area. In all cases gas diffusion influences the rate. During the chlorination of the oxides with Cl2 at low temperatures there was incomplete pore diffusion and the rate is restricted to the pore walls near the external surface. At high temperatures the rate is controlled by the diffusion of Cl2 through the gas film boundary layer around the oxide particle. During the chlorination by HCl the rate is controlled primarily by the counter current diffusion of HCl to the surface and of the reaction products away from the surface.