Nitric Acid

CAS RN: 7697-37-2

Other Properties

Heat of infinite dilution at 298.1 K: -7971 cal/mole; forms azeotrope with water so-called constant boiling acid at 68% nitric acid, bp: 120.5 deg C, density 1.41 at 20 deg C/4 deg C; Heat of Fusion: 2.503 kcal/mole; Density at -41.6 deg C (solid): 1895
Develops yellow color in the presence of light due to nitrogen oxide formation. Stains woolen fabrics and animal tissue a bright yellow; strong, monobasic acid; oxidizing agent. Reacts violently with combustible or readily oxidizable materials such as alcohols, turpentine, charcoal, organic refuse. Reacts with most metals to release hydrogen gas
Fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide. The density and vapor pressure of such solutions increase with the percentage of nitrogen dioxide present.
Heat of formation at 25 deg C: -174.10 kJ/mol
Free energy of formation at 25 deg C: -80.71 kJ/mol
Entropy at 25 deg C: 155.60 kJ/(mol)(K)
Heat of fusion: 2.503 kcal/mole
The freezing point curve for aqueous solutions of nitric acid has two maxima corresponding to melting points for the two hydrates of nitric acid: the monohydrate (77.77 wt% acid) at -37.62 deg C and the trihydrate (58.83 wt% acid) at -18.47 deg C. Local minima occur at 32, 71, and 91 wt % acid.
Weigh: 10.4 lb/gal, nitric acid, 40% or less; 12.6 lb/gal, nitric acid, over 40%; 12.5 lb/gal, nitric acid, fuming.
Molar enthalpy of fusion: 10.50 kJ/mol
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