What is the ΔGrxn for the ionization of 0.1245 M nitrous acid, HNO2, in a solution in which the [H3O+] = 5.55 x 10–4 M and [NO2–] = 1.2 x 10–4 M. Assume that T = 25 °C.

Useful constants:

Ka(HNO2) = 4.5 x 10¯4

Kw = 1.0 x 10¯14

R = 8.314 J/mol K