Abstract
The sound speeds of boric acid and sodium borate in water and 0.725 m NaCl have been measured from 0 to 50 °C and to near 1 molal. These results have been used to determine the partial molal adiabatic compressibilities of B(OH) 3 and NaB(OH) 4. The partial molal volumes, v(i), and compressibilities, k(i), have been used to estimate the changes in the volume (ΔV) and compressibility (Δk) for the dissociation of boric acid in water and average seawater (0.725 m NaCl, S A ~ 35 g/kg) B(OH) 3 + H 2O = H + + B(OH) - 4 where The calculated values of ΔV and Δk were used to estimate the effect of applied pressure (P) on the dissociation constants (K P/K 0) ln(K P/K 0)=-ΔVP/RT + 0.5ΔkP 2/RT The new values of Δk in water from 0 to 1000 bar give values of K P/K 0 that are in good agreement with the measured values. The values of K P/K 0 at P = 1942 bar in water are slightly higher than the measured values. The new calculated values of K P/K 0 in seawater from 0 to 25 oC and to P = 1000 bar are in good agreement with the measured values. This means that the contributions of boric acid to the alkalinity of seawater in deep waters are not affected by the new values of K P/K 0 determined from volume studies.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 83-92 |
| Number of pages | 10 |
| Journal | Geochimica et Cosmochimica Acta |
| Volume | 76 |
| DOIs | |
| State | Published - Jan 15 2012 |
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ASJC Scopus subject areas
- Geochemistry and Petrology
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Effect of pressure on the dissociation constant of boric acid in water and seawater. / Millero, Frank J; Ward, Gary K.; Surdo, Antonio Lo; Huang, Fen.
In: Geochimica et Cosmochimica Acta, Vol. 76, 15.01.2012, p. 83-92.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of pressure on the dissociation constant of boric acid in water and seawater
AU - Millero, Frank J
AU - Ward, Gary K.
AU - Surdo, Antonio Lo
AU - Huang, Fen
PY - 2012/1/15
Y1 - 2012/1/15
N2 - The sound speeds of boric acid and sodium borate in water and 0.725 m NaCl have been measured from 0 to 50 °C and to near 1 molal. These results have been used to determine the partial molal adiabatic compressibilities of B(OH) 3 and NaB(OH) 4. The partial molal volumes, v(i), and compressibilities, k(i), have been used to estimate the changes in the volume (ΔV) and compressibility (Δk) for the dissociation of boric acid in water and average seawater (0.725 m NaCl, S A ~ 35 g/kg) B(OH) 3 + H 2O = H + + B(OH) - 4 where The calculated values of ΔV and Δk were used to estimate the effect of applied pressure (P) on the dissociation constants (K P/K 0) ln(K P/K 0)=-ΔVP/RT + 0.5ΔkP 2/RT The new values of Δk in water from 0 to 1000 bar give values of K P/K 0 that are in good agreement with the measured values. The values of K P/K 0 at P = 1942 bar in water are slightly higher than the measured values. The new calculated values of K P/K 0 in seawater from 0 to 25 oC and to P = 1000 bar are in good agreement with the measured values. This means that the contributions of boric acid to the alkalinity of seawater in deep waters are not affected by the new values of K P/K 0 determined from volume studies.
AB - The sound speeds of boric acid and sodium borate in water and 0.725 m NaCl have been measured from 0 to 50 °C and to near 1 molal. These results have been used to determine the partial molal adiabatic compressibilities of B(OH) 3 and NaB(OH) 4. The partial molal volumes, v(i), and compressibilities, k(i), have been used to estimate the changes in the volume (ΔV) and compressibility (Δk) for the dissociation of boric acid in water and average seawater (0.725 m NaCl, S A ~ 35 g/kg) B(OH) 3 + H 2O = H + + B(OH) - 4 where The calculated values of ΔV and Δk were used to estimate the effect of applied pressure (P) on the dissociation constants (K P/K 0) ln(K P/K 0)=-ΔVP/RT + 0.5ΔkP 2/RT The new values of Δk in water from 0 to 1000 bar give values of K P/K 0 that are in good agreement with the measured values. The values of K P/K 0 at P = 1942 bar in water are slightly higher than the measured values. The new calculated values of K P/K 0 in seawater from 0 to 25 oC and to P = 1000 bar are in good agreement with the measured values. This means that the contributions of boric acid to the alkalinity of seawater in deep waters are not affected by the new values of K P/K 0 determined from volume studies.
UR - http://www.scopus.com/inward/record.url?scp=84855871043&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84855871043&partnerID=8YFLogxK
U2 - 10.1016/j.gca.2011.10.024
DO - 10.1016/j.gca.2011.10.024
M3 - Article
VL - 76
SP - 83
EP - 92
JO - Geochmica et Cosmochimica Acta
JF - Geochmica et Cosmochimica Acta
SN - 0016-7037
ER -