4. THE SOLUBILITY OF CALCIUM PHOSPHATE I. containing either HC1 or NaOH at different pH values and at various temperatures.") THE EFFECT OF pH AND OF AMOUNT OF SOLID PHASE BY ISIDOR GREENWALD (From the Department of Chemistry, New York University College of Medicine, New York) (Received for publication, .January 14, 1942) In 1937, Logan and Taylor (1) came to the conclusion “that the bone 5. The soil pH has been defined as the parameter most widely accepted as exerting a controlling influence on the availability of micronutrients to plants (Sanders, 1982). pH FIG. at pH8.0 and a minimum protein solubility at pH5.0 were observed (Table 2). All plants are affected by the extremes of pH but there is wide variation in their tolerance of acidity and alkalinity. FIGURE 1. between the temperature-controlled silica solubility curve and pH-controlled silica solubility curve. However, NaCl, Na 2 SO 4 and (NH 4) 2 SO 4 salts showed significant differences in their protein solubility within the pH ranges. The effect of pH on a weak acid (A) and a weak base (B) 3. As can be seen in Figure 2b and 3b, both in Well A or Well B, the solubility of amorphous silica increases significantly at pH > 7 in separator, and pH > 8 in weirbox. PARTICLE SIZE As the P.S decreases solubility increases due to increase in the surface area. 3) show that the points are on lines with slopes smaller than 2.0 for pH<9 and —2 for pH> 11, irrespective of the presence of Zn(OH) 2. --" 100 - 8O O ~ 60 O e- ~ 40 O r fl_ ~ 20 e- 0 "2.0 2.74 [ I I I J I I I I 2 4 6 8 10 pH FIG. Effect of NaCl concentration on protein solubility at pH8.0 FIGURE 2. ] S-So=solubility of ionized species pH of a substance is related to its pKa and the concentration of the ionized and unionized forms of the substance. SOIL pH RESULTS Soil pH effect on plant response A soil pH(CaCl2) of 5.2 to 8.0 provides optimum conditions for most agricultural plants (Figure 1). Soil pH has a great effect on the solubility or retention and lower solubility of metal cations occurring at high pH (Barrow, 1992). Determination of solubility: Solubility of Benzoic acid (S) in different pH buffer solution was estimated by acid-base titration method at room temperature (25 0C). Their results determined at 25°C (Fig. Soil pH for Some plants grow well over a wide Effect of pH and Ca:PA molar ratio on solubility of phytate phosphorus at low molar ratios of 0.5-2.74. In present work 100 ml of buffer solution of different pH (4.0, 7.0 and 9.0) were taken in different beakers and in each beaker At … We have examined the effect of pH and temperature on the solubility of 3‐(4‐heptylbenzoyl) benzoic acid (1), a surface active carboxylic acid with a pK a of 4.83 and a critical micelle concentration (cmc) of 4 × 10 −4 M. Our results show that below a pH of 7.0 and a temperature of 50°C, the solubility of 1 is less than the cmc; under these conditions, 1 behaves like a typical weak acid. Effect of pH and Ca,PA molar ratio on solubility of calcium at high molar ratios of 4-12.67.