The reaction of 2Br2 + 2H2O → 4HBr + O2 involves the oxidation of bromine (Br2) by water (H2O) to form hydrogen bromide (HBr) and oxygen (O2). Bromine is reduced to HBr, and oxygen gas is released as a byproduct.
I suppose that the reaction is the following: ZrBr4 + H2O----------ZrOBr2 + 2 HBr
To balance the chemical equation Br2 + H2O + SO2 = H2SO4 + HBr, you need to start by balancing the elements that appear in the equation. First, balance the bromine atoms on each side, then balance the hydrogen, oxygen, sulfur, and finally the oxygen atoms, making sure the same number of each type of atom is present on both sides of the equation. The balanced equation is 2Br2 + 2H2O + 3SO2 = H2SO4 + 4HBr.
I2 + 10 hno3 = 2 hio3 + 10 no2 + 4 h2o
2PbS + 3O2 ----> 2PbO + 2SO2