What is the apparent air-water partition constant

Question

Problem

Sodium azide (NaN3) is used as a component of air bags in automobiles (=106 kg in 1995). When dissolved in water it gives rise to volatile hydrazoic acid, HN₃. It is a weak acid and the reaction HN₃ H⁺ + N₃^- has a pK_a value of 4.65 at 25^oC. The intrinsic Henry's constant Kaw for the neutral species is 0.0034 at 25^oC (Betterton and Robinson, 1997).

(a) What is the apparent air-water partition constant at pH 7?

(b) The enthalpy of solution is -31 kJ/mol. Calculate the air-water partition constant at 4^oC.

(c) In a wastewater at 25^oC, if the azide concentration is 0.1 mM at pH 6.5, will the gas phase HN₃ exceed the threshold limit value (TLV) of 0.1 ppmv?

The response should include a reference list. Double-space, using Times New Roman 12 pnt font, one-inch margins, and APA style of writing and citations.