pHn.

Brit.

/ˌpiːˈeɪtʃ/, U.S.

/ˌpiˈeɪtʃ/

Forms: 1900s– pH, 1900s– p_H (now rare), 1900s– p_H⁺ (now rare), 1900s– P_h (now rare), 1900s– PH (now rare), 1900s– P_H⁺ (now rare), 1900s– P h (now rare).

Origin: A borrowing from German. Etymon: German pH·.

Etymology: < German p_H· (S. P. L. Sörensen 1909, in Biochem. Zeitschr. 21 134; now pH ) < p (apparently in German Potenz power: see potency n.) + H·, former chemical symbol for the hydrogen ion (now H⁺). Compare French pH (1909 as p_H⁺ in a paper by the same author, in Comptes-rendus des trav. du lab. de Carlsberg 8 4).Sörensen's original form p_H· is apparently not attested in English contexts.

Chemistry.

A number expressing the acidity or alkalinity of a solution (or of a medium containing a solution, such as soil, blood, etc.) equal to the logarithm to the base 10 of the reciprocal of the effective concentration (activity) of hydrogen ions (in moles per litre).A pH of 7 corresponds to a neutral solution, one less than 7 to an acidic solution, and one greater than 7 to an alkaline solution.

ΘΚΠ

the world > matter > chemistry > units or measurements > [adjective] > measure of acidity or alkalinity

pH1909

1909 Jrnl. Chem. Soc. 96 i. 861 The optimal concentration was p_H = 4·4 to 4·6.

1920 W. M. Clark Determination Hydrogen Ions i. 26 As a matter of typographical convenience we shall adopt pH in place of P_H⁺.

1921 Jrnl. Nat. Dental Assoc. 8 653/1 He uses agar with a P h value of 8·1 as a basis for blood agar.

1937 W. C. Pierce & E. L. Haenisch Quantitative Anal. viii. 121 Acid-base indicators are highly colored organic dyes which exhibit a change in color when the pH of a solution is changed.

1952 C. E. L. Phillips Small Garden iii. 25 For general garden purposes in this country best results come from a neutral or slightly acid pH reading.

1974 P. Svendsen Introd. Animal Physiol. xiii. 143 The maximum acidity of the wine is about pH 4·5.

1995 Org. Gardening Jan. 68/3 In a 6.0 or lower pH soil, nothing goes right for peas.

1997 G. S. Helfman et al. Diversity of Fishes vii. 91/1 Lowering the blood pH of arctic grayling..increases Na⁺ influx and decreases Cl⁻ influx at the gills.

Compounds

C1.

pH-dependent adj.

ΚΠ

1949 Jrnl. Amer. Chem. Soc. 71 2507/2 This will occur if the stability of the complex is pH dependent.

1972 Brit. Jrnl. Nutrition 28 389 The pH-dependent rearrangements have also to be borne in mind when performing administration experiments with formylfolates in metabolic studies.

2000 Proc. National Acad. Sci. U.S.A. 97 14824/2 The conversion from IAOx is highly pH dependent.

pH meter n.

ΚΠ

1932 Science 28 Oct. 10a (advt.) The Cambridge Electrometer Tube pH Meter illustrated, provides a direct reading instrument calibrated in pH units.

1970 P. Anderson Tau Zero 52 The workbench behind which she stood was barricaded with test tubes, flasks, a pH meter, a stirrer, a blender, and more.

1992 RS Components: Electronic & Electr. Products July 1138/3 A self-contained battery-operated pH meter covering the range 0 to 14 pH. For use in determining the acidity/alkalinity/neutrality of chemical solutions.

pH scale n.

ΚΠ

1916 Proc. National Acad. Sci. U.S.A. 2 690 The salt error could not be determined more accurately with these tubes since they read down only to 0.1 on the PH scale.

1973 F. G. Shinskey pH & pIon Control in Process & Waste Streams iii. 57 The pH scale is not bound to the limits of 0 to 14.

2001 Guardian 11 Jan. (Science section) 2/6 At the other end of the pH scale are the alkaliphiles. These are found in various types of salt lake and carbonate-laden soils.

pH value n.

ΚΠ

1915 Science 19 Nov. 735/1 The p_H values given were obtained by titration with phosphate and acetate mixtures.

1946 J. W. Day Harvest Adventure iii. 44 Every acre of arable land has had a dressing of chalk. In all..some 30,000 tons have been put down, the idea being to maintain a pH-value of 5.

1992 D. M. Elsom Atmospheric Pollution (BNC) (ed. 2) 84 An even lower pH value of below 2.0 was unofficially recorded during a rainstorm in Wheeling, West Virginia, in 1978.

C2.

pH-stat n. a device for automatically maintaining a solution at constant pH.

ΘΚΠ

the world > matter > chemistry > equipment or apparatus > [noun] > miscellaneous apparatus

bain1477

speculum1650

filtering paper1651

wheel-fire1662

filter paper1670

sun furnace1763

respirator1789

candle-ball1794

rectifier1822

candle-bomb1823

filter1823

oxyhydrogen blowpipe1823

shade1837

graduator1839

pipette1839

thistle funnel1849

pressure tube1852

ozonizer1858

dialyser1861

Liebig condenser1861

Sprengel pump1866

Sprengel tube1866

water softener1867

mercury pump1869

Bunsen burner1870

dialysator1877

test-mixer1877

tube-condenser1877

Kipp1879

reflux condenser1880

policeman1888

converter1889

pressure boiler1891

spot plate1896

hydrogen electrode1898

sampler1902

reactor1903

fume-chamber1905

Permutit1910

microburner1911

salt bridge1915

precipitator1919

Raschig ring1920

microneedle1921

titrator1928

laboratory coatc1936

spray tower1937

precipitron1938

ion exchanger1941

potentiostat1942

chemostat1950

Knudsen pipette1951

pH-stat1956

cryopump1958

1956 Jrnl. Amer. Chem. Soc. 78 1862/1 This operation was performed automatically by a ‘pH-stat’ constructed by Mr. T. V. Parke.

1974 D. T. Sawyer & J. L. Roberts Exper. Electrochem. for Chemists ix. 417 In general autotitrators that work with a preset endpoint lend themselves to application as pH-stats.

2000 Proc. National Acad. Sci. U.S.A. 97 5069/2 We found that the maize..had somewhat higher protein digestibility (15% higher filtration volume by using the pH stat in vitro protein digestibility method).

This entry has been updated (OED Third Edition, December 2005; most recently modified version published online March 2022).

单词	ph
释义	pHn. Brit. /ˌpiːˈeɪtʃ/, U.S. /ˌpiˈeɪtʃ/ Forms: 1900s– pH, 1900s– p_H (now rare), 1900s– p_H⁺ (now rare), 1900s– P_h (now rare), 1900s– PH (now rare), 1900s– P_H⁺ (now rare), 1900s– P h (now rare). Origin: A borrowing from German. Etymon: German pH·. Etymology: < German p_H· (S. P. L. Sörensen 1909, in Biochem. Zeitschr. 21 134; now pH ) < p (apparently in German Potenz power: see potency n.) + H·, former chemical symbol for the hydrogen ion (now H⁺). Compare French pH (1909 as p_H⁺ in a paper by the same author, in Comptes-rendus des trav. du lab. de Carlsberg 8 4).Sörensen's original form p_H· is apparently not attested in English contexts. Chemistry. A number expressing the acidity or alkalinity of a solution (or of a medium containing a solution, such as soil, blood, etc.) equal to the logarithm to the base 10 of the reciprocal of the effective concentration (activity) of hydrogen ions (in moles per litre).A pH of 7 corresponds to a neutral solution, one less than 7 to an acidic solution, and one greater than 7 to an alkaline solution. ΘΚΠ the world > matter > chemistry > units or measurements > [adjective] > measure of acidity or alkalinity pH1909 1909 Jrnl. Chem. Soc. 96 i. 861 The optimal concentration was p_H = 4·4 to 4·6. 1920 W. M. Clark Determination Hydrogen Ions i. 26 As a matter of typographical convenience we shall adopt pH in place of P_H⁺. 1921 Jrnl. Nat. Dental Assoc. 8 653/1 He uses agar with a P h value of 8·1 as a basis for blood agar. 1937 W. C. Pierce & E. L. Haenisch Quantitative Anal. viii. 121 Acid-base indicators are highly colored organic dyes which exhibit a change in color when the pH of a solution is changed. 1952 C. E. L. Phillips Small Garden iii. 25 For general garden purposes in this country best results come from a neutral or slightly acid pH reading. 1974 P. Svendsen Introd. Animal Physiol. xiii. 143 The maximum acidity of the wine is about pH 4·5. 1995 Org. Gardening Jan. 68/3 In a 6.0 or lower pH soil, nothing goes right for peas. 1997 G. S. Helfman et al. Diversity of Fishes vii. 91/1 Lowering the blood pH of arctic grayling..increases Na⁺ influx and decreases Cl⁻ influx at the gills. Compounds C1. pH-dependent adj. ΚΠ 1949 Jrnl. Amer. Chem. Soc. 71 2507/2 This will occur if the stability of the complex is pH dependent. 1972 Brit. Jrnl. Nutrition 28 389 The pH-dependent rearrangements have also to be borne in mind when performing administration experiments with formylfolates in metabolic studies. 2000 Proc. National Acad. Sci. U.S.A. 97 14824/2 The conversion from IAOx is highly pH dependent. pH meter n. ΚΠ 1932 Science 28 Oct. 10a (advt.) The Cambridge Electrometer Tube pH Meter illustrated, provides a direct reading instrument calibrated in pH units. 1970 P. Anderson Tau Zero 52 The workbench behind which she stood was barricaded with test tubes, flasks, a pH meter, a stirrer, a blender, and more. 1992 RS Components: Electronic & Electr. Products July 1138/3 A self-contained battery-operated pH meter covering the range 0 to 14 pH. For use in determining the acidity/alkalinity/neutrality of chemical solutions. pH scale n. ΚΠ 1916 Proc. National Acad. Sci. U.S.A. 2 690 The salt error could not be determined more accurately with these tubes since they read down only to 0.1 on the PH scale. 1973 F. G. Shinskey pH & pIon Control in Process & Waste Streams iii. 57 The pH scale is not bound to the limits of 0 to 14. 2001 Guardian 11 Jan. (Science section) 2/6 At the other end of the pH scale are the alkaliphiles. These are found in various types of salt lake and carbonate-laden soils. pH value n. ΚΠ 1915 Science 19 Nov. 735/1 The p_H values given were obtained by titration with phosphate and acetate mixtures. 1946 J. W. Day Harvest Adventure iii. 44 Every acre of arable land has had a dressing of chalk. In all..some 30,000 tons have been put down, the idea being to maintain a pH-value of 5. 1992 D. M. Elsom Atmospheric Pollution (BNC) (ed. 2) 84 An even lower pH value of below 2.0 was unofficially recorded during a rainstorm in Wheeling, West Virginia, in 1978. C2. pH-stat n. a device for automatically maintaining a solution at constant pH. ΘΚΠ the world > matter > chemistry > equipment or apparatus > [noun] > miscellaneous apparatus bain1477 speculum1650 filtering paper1651 wheel-fire1662 filter paper1670 sun furnace1763 respirator1789 candle-ball1794 rectifier1822 candle-bomb1823 filter1823 oxyhydrogen blowpipe1823 shade1837 graduator1839 pipette1839 thistle funnel1849 pressure tube1852 ozonizer1858 dialyser1861 Liebig condenser1861 Sprengel pump1866 Sprengel tube1866 water softener1867 mercury pump1869 Bunsen burner1870 dialysator1877 test-mixer1877 tube-condenser1877 Kipp1879 reflux condenser1880 policeman1888 converter1889 pressure boiler1891 spot plate1896 hydrogen electrode1898 sampler1902 reactor1903 fume-chamber1905 Permutit1910 microburner1911 salt bridge1915 precipitator1919 Raschig ring1920 microneedle1921 titrator1928 laboratory coatc1936 spray tower1937 precipitron1938 ion exchanger1941 potentiostat1942 chemostat1950 Knudsen pipette1951 pH-stat1956 cryopump1958 1956 Jrnl. Amer. Chem. Soc. 78 1862/1 This operation was performed automatically by a ‘pH-stat’ constructed by Mr. T. V. Parke. 1974 D. T. Sawyer & J. L. Roberts Exper. Electrochem. for Chemists ix. 417 In general autotitrators that work with a preset endpoint lend themselves to application as pH-stats. 2000 Proc. National Acad. Sci. U.S.A. 97 5069/2 We found that the maize..had somewhat higher protein digestibility (15% higher filtration volume by using the pH stat in vitro protein digestibility method). This entry has been updated (OED Third Edition, December 2005; most recently modified version published online March 2022). < n.1909
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