11 Predict which of the following reactions would be product

11. Predict which of the following reactions would be product favored (Keq > 1.0) at equilibrium at 25°C.

(1) HBrO3(aq) + ClO3(aq) HClO3(aq) + BrO3(aq)

(2) H2CO3(aq) + NO3(aq) HNO3(aq) + HCO3(aq)

(3) HSO4(aq) + PO43(aq) HPO42(aq) + SO42(aq)

(4) HCO3(aq) + H2O(aq) H3O+(aq) + CO32(aq)

(5) none of the above are predicted to be product favored at equilibrium at 25°C

The answer is (3) but i need to know why/how

The acid base equilibrium always lies towards the weak acid - base or the weak acid-conjugate base pair.

1)in the firt equation

HBrO3 is weker acid than HClO3. So the equilibrium lies left that is Keq<1

2) HNO3 stronger acid than H2CO3 . Thus the equilibrium lies towards reactants, Keq <1

3) HPO4^-2 is weaker than HSO4- .thus the equilibrium lies to wards products . hence Keq >1

4) simialrly HCO3- is weaker acid than H3O+