Question

How many moles of water are produced if 5.43 mol PbO2 are consumed

Answer 1

It has to be understood that 2 moles of oxygen are there in each mole of PbO2. Then it has to be calculated for 2 moles of oxygen.

Amount of oxygen = 2 * 5.43 moles
                              = 10.86 moles
Now it is also a fact that each mole of H2O contains 1 mole of oxygen. Then it can be easily concluded that 10.86 moles of water will be produced. I hope the procedure is clear enough for you to understand.

Answer 2

this is a stoichiometry based problem

We can solve this by just knowing the balanced chemical equation.The reaction where PbO2 is used and water is produced is

Pb + PbO2 + 2H2SO4 ----> 2PbSO4 + 2H2O

This is reaction in lead storage battery

so here as per balanced equation one mole of PbO2 is consumed giving two moles of water

so if 5.43 moles of PbO2 we will get = 2 X 5.43 moles of water = 10.86 moles