Select the correct answer. Which compounds are acting like Brønsted-Lowry acids in the following acid-base equilibrium?

HCO3− + H2O H2CO3 and OH−

A.
H2O and OH−

B.
HCO3− and OH−

C.
H2O and H2CO3

D.
HCO3− and H2CO3

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.