First and second dissociation constants of deuterio-o-phthalic acid in D/sub 2/O from 5 to 50/sup 0/C
The first and second dissociation constants of deuterio-o-phthalic acid in deuterium oxide have been determined by the emf method over the temperature range of 5 to 50/sup 0/C. The pD values for potassium deuterium phthalate have been calculated from these two constants and experimentally verified. The thermodynamic properties for the dissociation of deuterio-o-phthalic acid have been evaluated. At 25/sup 0/C, these values in the molality scale are: pK /SUB 1A/ = 3.505, pK /SUB 2A/ = 5.890, and pD = 4.518. From K /SUB 1A/ and K /SUB 2A/ , respectively: ..delta..G/sup 0/ = 20.003, 33.582 kJ-mol/sup -1/; ..delta..H/sup 0/ = 2.851, 2.208 kJ-mol/sup -1/; ..delta..S/sup 0/ = -76.7, -105.2 J-mol/sup -1/-K/sup -1/; and ..delta..C/sup 0/ /SUB p/ = -52.7, -315.6 J-mol/sup -1/-K/sup -1/. The isotope effect is discussed.
- Research Organization:
- National Bureau of Standards, Gaitherburg, MD
- OSTI ID:
- 7202448
- Journal Information:
- J. Solution Chem.; (United States), Journal Name: J. Solution Chem.; (United States) Vol. 15:6; ISSN JSLCA
- Country of Publication:
- United States
- Language:
- English
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ALKALI METAL COMPOUNDS
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CHLORIDES
CHLORINE COMPOUNDS
DEUTERIUM COMPOUNDS
DIAGRAMS
DICARBOXYLIC ACIDS
DISSOCIATION
DISSOCIATION ENERGY
ELECTROCHEMICAL CELLS
ELECTRODES
ELECTROMOTIVE FORCE
ENERGY
HALIDES
HALOGEN COMPOUNDS
HEAVY WATER
HYDROGEN COMPOUNDS
ISOTOPE EFFECTS
LEAD CHLORIDES
LEAD COMPOUNDS
LEAD HALIDES
MEDIUM TEMPERATURE
NITRATES
NITROGEN COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PH VALUE
PHTHALATES
PHTHALIC ACID
POTASSIUM COMPOUNDS
POTENTIOMETRY
QUANTITY RATIO
SILVER CHLORIDES
SILVER COMPOUNDS
SILVER NITRATES
TITRATION
TRANSITION ELEMENT COMPOUNDS
WATER