Studies on soil reaction: III. The determination of the hydrogenion concentration of soil suspensions by means of the hydrogen electrode

1925 ◽  
Vol 15 (2) ◽  
pp. 201-221 ◽  
Author(s):  
Edward M. Crowther
Keyword(s):  
Dilution Effect ◽  
Ion Concentration ◽  
Soil Reaction ◽  
Neutral Salt ◽  
Alkaline Soils ◽  
Hydrogen Electrode ◽  
Hydrogen Ion Concentration ◽  
Base Exchange ◽  
Buffer Action ◽  
Hydrogenion Concentration

A hydrogen electrode apparatus for soils is described. Similar or adjacent soils may show considerable differences inpH value, with no changes in their degrees of buffer action, as shown in titration curves with lime water. In such cases the conventional “lime requirements” are correlated with thepH values, but no such relation holds in dissimilar soils. ThepH value of a soil suspension is intimately connected with the nature and amount of the cations present. Neutral salts markedly increase the hydrogen ion concentration of both acid and slightly alkaline soils. Sodium salts, including the hydroxide, give lower hydrogenion concentrations than the corresponding potassium or calcium salts, and chlorides give lowerpH values than sulphates. The degree of buffer action (slope of titration curve) is unaffected by the addition of a neutral salt. Previous extraction of a soil with water causes a considerable increase i n thepH value of its suspensions. A number of soils showed a regular increase of about 0·1 inpH. value for twofold dilution. The “salt effect” and “dilution” effect appear to be of the same type. It is recommended that the soil-water ratio of 1:5 be generally adopted. The indicator methyl red gives erroneouspH values in turbid soil suspensions owing to the absorption of the red form, which is apparently a cation capable of undergoing “base exchange” with the soil.

The influence of hydrogen-ion concentration on the decomposition of soil Organic matter by hydrogen peroxide (With two text-figures.)

1932 ◽  
Vol 22 (1) ◽  
pp. 92-100 ◽  
Author(s):  
J. S. Hosking
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Matter ◽  
Acid Soils ◽  
Clay Content ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Soil Reaction ◽  
Definite Function ◽  
Alkaline Soils ◽  
Hydrogen Ion Concentration

The decomposition of the organic matter of the soil by means of hydrogen peroxide is shown to be a function of the hydrogen-ion concentration of the soil, alkaline soils permitting of a very low degree of oxidation, while with acid soils up to 90 per cent, of the organic matter is destroyed.The results obtained with a range of soils suggest that a portion of the organic matter is oxidised irrespective of the soil reaction, while the oxidation of the remainder is a definite function of the hydrogen-ion concentration, the relation being expressed by the equationThe proportion of the organic matter oxidised further appears to be a definite function of the clay content of the soil. Alkaline soils containing free manganese dioxide also show small losses.

scholarly journals Spectrometric determinations of the effect of a neutral salt on the dissociation of acetic acid

1930 ◽  
Vol 130 (812) ◽  
pp. 1-16
Keyword(s):  
Acetic Acid ◽  
Methyl Orange ◽  
Preceding Paper ◽  
Ion Concentration ◽  
Neutral Salt ◽  
Apparent Dissociation Constant ◽  
Hydrogen Ion Concentration ◽  
K Value ◽  
Degree Of Dissociation ◽  
Colour Measurements

This paper gives an account of an extension of the work contained in the preceding paper (Sidgwick, Worboys and Woodward). For the first part the simple photoelectric colorimeter described in that paper was used. For the Second part a new type of flicker photometer was constructed. The principle of both instruments is the same, and has been given in the previous paper together with the theory of the colour changes of methyl orange, the indicator used throughout. The colour measurements allow us to determine the value of the apparent dissociation constant K of methyl orange in presence of various concentrations of natural salt. At a given salt concentration therefore the use of the appropriate K value will enable us to calculate the true hydrogen ion concentration of such a solution from its colour. In this way the degree of dissociation of acetic acid has been investigated in presence of different amounts of the neutral salt potassium bromide.

The hydrogen-ion concentration of heavy alkaline soils

1923 ◽  
Vol 13 (3) ◽  
pp. 321-332 ◽  
Author(s):  
A. F. Joseph ◽  
F. J. Martin
Keyword(s):  
Clay Soil ◽  
Colorimetric Method ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Residual Soil ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Soil Suspension ◽  
Hydrogen Ion Concentration ◽  
Routine Work

(1) The colorimetric method is unsuited to the examination of heavy, alkaline soils owing to the turbidity of the suspension.(2) Where the nature of the suspension permits of colorimetric determinations being made, they agree with those obtained electrometrically: with the latter method practically identical results are obtained using soil-water mixtures or moderately clear extracts.(3) No disturbing effect is likely to be introduced by amounts of nitrate up to 500 parts per million of soil.(4) Owing to the effect on the pH of a soil suspension caused by varying the proportion of water and time of extraction, these conditions should be fixed for routine work. We have found 1 hour's extraction with 5 parts of water satisfactory.(5) On account of the amphoteric or buffer nature of clay, soil shifts the reaction of acids and alkalis in the direction of neutrality.(6) The effect of sodium salts on a soil is to displace aluminium and so reduce alkalinity: the residual soil after leaching is found to be more alkaline.(7) The effect of drying alkaline soil is to cause the pH of the extract to be lower than that obtained from the undried soil. If however the time of extraction is prolonged, the differences disappear almost entirely.

Di Brom Thymol Sulhpone Phthalein as a Reagent for Determining the Hydrogen Ion Concentration of Living Cells

1922 ◽  
Vol 12 (4) ◽  
pp. 781-784 ◽  
Author(s):  
W. R. G. Atkins
Keyword(s):  
Sea Water ◽  
Living Cells ◽  
Marine Organisms ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Toxic Action ◽  
Thymol Blue ◽  
Neutral Salt ◽  
Dilute Solution ◽  
Hydrogen Ion Concentration

1. Brom thymol blue may be used in dilute solution for ascertaining the hydrogen ion concentration of certain marine organisms. It penetrates slowly, but the stained portions remain actively motile, so its toxic action does not appear to be great at the dilutions found serviceable.2. The animals studied gave values from pH6·2 to about pH7·5, though possibly the more alkaline end of the range may be pathological. About pH0·2 should be subtracted from these figures for neutral salt error. The sea water used was initially at pH8·2, corrected.

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