Final answer:
To balance the chemical equation, use stoichiometry to determine the mass of AgBr formed, and calculate the percent yield of the reaction.
Step-by-step explanation:
To balance the chemical equation Na2SO3 + NaBr -> NaBr + Na2SO4, the balanced equation is 2NaBr + SO2 + 2H2O -> 2NaHSO3. This means that for every 2 moles of NaBr and SO2, 2 moles of NaHSO3 are formed.
To determine the mass of AgBr formed in the reaction, we need to use stoichiometry. The balanced equation is 2AgNO3 + NaBr -> 2AgBr + NaNO3. From this equation, we can see that 2 moles of AgBr are formed for every 2 moles of AgNO3. We can use the molar mass of AgBr to convert moles to grams.
The percent yield of the reaction can be calculated by dividing the actual yield (given as 1.25 g) by the theoretical yield (calculated from stoichiometry) and multiplying by 100%.