Electrical conductivity of acidic chloride solutions
- PDF / 494,968 Bytes
- 6 Pages / 603.28 x 783.28 pts Page_size
- 75 Downloads / 283 Views
I.
INTRODUCTION
RECENTLY the authors studied the electrical conductivity of acidic sulfate solutions and found that the water activities of these solutions play an important role in determining their electrical conductivity. This study aims to investigate the contributions of various ionic species existing in aqueous solutions of HC1-MC1, to their electrical conductivities, and to expose the relationship between equivalent electrical conductivity of H § and the activity of water. Also the applicability of Walden's rule, namely, that the product of equivalent conductance and viscosity is constant, for the behavior of the H § ion was examined by means of conductivity and viscosity measurements in a range of temperatures and ionic strengths.
II.
EXPERIMENTAL PROCEDURES
Electrical conductivity measurements were made with a conductivity meter (type CM-30ET, TOA Co., Japan) and a high conductivity cell (type CG-210PL). The cell constant was determined by standardizing at 298 K with KC1 solution whose specific resistivity is accurately known. The electrical conductivities of HC1 solutions determined by using this apparatus agree with those reported in the literature 2 within 0.5 pct accuracy. Also, the viscosity measurements were made with a Canon-Fenske viscometer. The activities of water in the aqueous HCI-KC1 solutions were determined by a transpiration method at different temperatures, as detailed in a previous paper. 3 All determinations were made in a water bath thermostatted at temperatures of 288, 298, 308, and 318 K with an accuracy of -+0.1 K by using a temperature sensor (type TH-505). Reagent grade chemicals were used without further purification, and deionized water with a specific resistivity of 5 x 106 ohm cm was used to prepare aqueous solutions. Concentrations of HC1 were adjusted at five levels consisting of 1.0, 1.5, 2.0, 2.5, and 3.0 mol dm -3, while those
of chloride were elected at three levels of 0.5, 1.0, and 1.5 mol dm -3.
III.
EXPERIMENTAL RESULTS
A. Electrical Conductivity Electrical conductivities of various chloride solutions have been measured by many researchers and reported elsewhere. 4 Prior to determining the electrical conductivities of mixed aqueous solutions of HC1-MCI,, the present authors also measured the electrical conductivities of neutral solutions containing MC1, alone, for comparison with published values. The results obtained show satisfactory agreement within experimental error. Figure 1 shows the specific conductivities of aqueous solutions in the HC1-KC1 system at 298 K. At constant HC1 concentration, the specific conductivity increases linearly with increasing KC1 concentration, but the slope decreases at higher HC1 concentrations. In other words, the effect of KC1 is less significant in more concentrated HC1 solutions. Figure 2 shows the results for NaC1, NiC12, MgC12, and CdCI2, as well as those of KC1 from Figure 1 at 298 K and at constant HCI concentrations of 1.0, 1.5, and 2.0 mol dm -3. In contrast to the increasing specific conductivity with the increasing
Data Loading...
