Which equation represents the standard enthalpy of formation, Hfo, of HNO2(aq) at 25 oC? Group of answer choices H2(g) N2(g) O3(g) HNO3(aq) H(g) N(g) O2(g) HNO2 (aq) HNO2 (aq) H2 (g) N2 (g) O2(g) HNO2 (aq) H(g) N(g) 2 O(g) H2(g) N2 (g) O2 (g) HNO2(aq)