Base on my research and further investigation about the said problem, the possbile answer would be this one.
1. calculate the g of PbO in the 272 g lead crystal (19% PbO)
272 g x 19 /100 = xxx g PbO
xxx g PbO/molecular mass of PbO = moles PbO
2. write and balance the equation of neutralization of PbO and sodium sulfide.
PbO + sodium sulfide -> sodium oxide + lead sulfide
3. Calculate the moles of sodium sulfide that will react with the moles of PbO
4. Convert the moles of sodium sulfide to g of sodium sulfide