The first step to answer this question is to balance the given equation:
[tex]BaBr_2+K_2SO_4\rightarrow2KBr+BaSO_4[/tex]
According to this, one mole of BaBr2 produces 2 moles of KBr. Use this information to find how many moles of KBr will be produced from 17.3 moles of BaBr2:
[tex]17.3molBaBr_2\cdot\frac{2molKBr}{1molBaBr_2}=34.6molKBr[/tex]
It means that the correct answer is the first choice a. 34.6.
