Hydrogen carbonates, HCO

Some 5% of the CO2 arising in the tissues is covalently bound to the N terminus of hemoglobin and transported as carbaminohemoglo-bin (not shown). About 90% of the CO2 is first converted in the periphery into hydrogen carbonate (HCOs"), which is more soluble (bottom). In the lungs (top), CO2 is regenerated again from HCOs" and can then be exhaled. 

The equations that represent the reactions with water support the prediction that NH4NO3 dissolves to form an acidic solution and Na3P04 dissolves to form a basic solution. Calcium chloride is the salt of a strong base-strong acid, so neither ion reacts with water and the solution is neutral. Both ions in ammonium hydrogen carbonate react with water. Because Kt, for HCOs" is greater than for NH4, the salt dissolves to form a weakly basic solution. 

An important function of the secreted H"" ions is to promote HCOs resorption (top right). Hydrogen carbonate, the most important buffering base in the blood, passes into the primary urine quantitatively, like all ions. In the primary urine, HCOa reacts with H"" ions to form water and CO2, which returns by free diffusion to the tubule cells and from there into the blood. In this way, the kidneys also influence the C02/HC03 buffering balance in the plasma. 

Carbon dioxide, C02, and its derivatives, the carbonates, are already familiar to the reader it should be pointed out that the basicities of both the carbonate ion, CO3", and the hydrogen carbonate ion, HCO ", preclude formation of the carbonates of metals whose ions are decidedly acidic thus, neither carbonates nor bicarbonates of Al3+, Cr3+, or Fe3+ have been reported. 

Carbon dioxide, produced by oxidation of substances in the tissues, is carried by the blood to the lungs. Part of it is in solution as carbonic acid, and part as hydrogen carbonate ion, HCO -. If the pH of the blood is 7.4, what fraction is carried as the ion ... 

Write the acid ionization equation and ionization constant expression for the hydrogen carbonate ion (HCO ). 

Ammonium Bicarbonate. Acid ammonium carbonate ammonium hydrogen carbonate. CHsNO, mot wt 79.06. C 15-19%. H 6.38%, N 17.72%. O 60.71%. NH4-HCO,. Occurs in the urine of alligators Coulson, Hernandez, Proc. Soc. Exp. Biot. Med. 88, 682 (1955). Usually prepd by passing an excess of carbon dioxide through coned ammonia water- Manuf Hrii. pat. 304,872 (1927 to I.G. 

The quantity of free carbon dioxide in water can be calculated from the determination of basic neutralization capacity up to pH 8.3 (BNC8 3, total acidity). In this case, free COj reacts with an alkaline titrant to form hydrogen carbonate (CO2 + OH — HCO ). Provided that the whole basic neutralization capacity up to pH 8.3 consists only of free carbon dioxide, its weight concentration (c(C02)) can be calculated from the following equation ... 

NH4 " NO, S04 OH CjHjO, Ammonium Nitrate Sulfate Hydroxide Acetate CO, HCO, PO4 HP04 H2PO4- Carbonate Hydrogen carbonate Phosphate Hydrogen phosphate Dihydrogen phosphate... 

C(=NH)(NH,)iniNO, Guani-donium nitrate, 1 94, 96, 97 [C(NH2) (N,H,)]HCOs Amino-guanidoniuiu hydrogen carbonate, 8 45... 

Hydroformylation usually involves the production of an aldehyde from hydrogen, carbon monoxide and ethylene using a catalyst such as RhH(CO)(PPh3)3, HCo(CO)3P Bu3, R3P(CO)3Co+ Co(CO)4 or [Bu3PPtCl2l2SnCl2. These catalysts enable the process to work at lower temperatures and pressures than were required by previously used catalysts such as Co2(CO)s. Most in current use is RhH(CO) (PPh3)3 which can secure over 95% conversion in scheme (12.352). 

Rainwater is naturally acidic, with a pH range of 5 to 6, and can become more acidic when it comes into contact with decaying plant matter. Because carbonate ion is the conjugate base of the weak add, hydrogen carbonate ion (HCOs, it readily combines with hydrogen ion. 

Although carbonic acid cannot be isolated as a pure compound, hydrogen carbonates (bicarbonates) and carbonates can be obtained by neutralizing carbonic acid solutions. Partial neutralization produces HCOs , and complete neutralization gives COs . 

The acid is diprotic with a base such as sodium hydroxide it may form both a normal salt, Na2C0.3, and an acid salt, NaHCOs. The normal salt contains the carbonate ion, CO3—, and the acid salt contains the hydrogen carbonate ion, HCOs. ... 

The process can be carried out by running a solution of ammonium nitrate into the nuclear reactor, where it is exposed to neutrons. The carbon that is made in this way is in the form of the hydrogen carbonate ion, HCO.3", and it can be precipitated as barium carbonate by adding barium hydroxide solution. The samples of radioactive carbon are very strongly radioactive, containing as much as 5% of the radioactive isotope. 

Carbonic acid is in equilibrium with the hydrogen carbonate ion, HCOs , which is in turn in equilibrium with the carbonate ion, CO. Each equilibrium has an associated acid-ionization constant. For the loss of the first proton. 

Left Calcium hydroxide solution with bromthymol-blue indicator. Center Carbon dioxide from dry ice reacts with calcium ion to precipitate calcium carbonate. Right In an excess of carbon dioxide,the calcium carbonate dissolves to form a solution of calcium ion and hydrogen carbonate ion, HCOs". In this acidic solution, bromthymol blue changes to a yellow color. 

Abnormal electrolyte concentrations in blood serum can indicate the presence of disease. The ion concentrations that vary as a result of disease are Na+, K+, Cl , and HCO J. Sodium ion concentration is a good indicator of the water balance between blood and tissue cells. Unusual potassium ion levels can indicate kidney or gastrointestinal problems. Chloride ion is the anion that balances the positive charge of the sodium ion in the fluid outside the cells. It also diffuses into a cell to maintain normal electrolyte balance when hydrogen carbonate ions diffuse out of the cell into the blood. Table IB shows medical conditions associated with electrolyte imbalances. 

Example 13 Calculate the basic ionization constant of bicarbonate (hydrogen carbonate) ion, HCO . 

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