Final answer:
To completely react with 45.5 g of HF, 16.7 g of Sn are needed. Correct option is c.
Step-by-step explanation:
To determine how many grams of Sn are needed to completely react with 45.5 g of HF, we first need to convert the grams of Sn to moles of Sn using its molar mass. The molar mass of Sn is 118.7 g/mol. So, we divide 45.5 g by the molar mass to get 0.3838 mol of Sn.
Next, we use the mole ratio between Sn and HF from the balanced equation. The ratio is 1 mole of Sn to 2 moles of HF. Multiplying 0.3838 mol of Sn by this ratio gives us 0.7676 mol of HF.
Finally, we convert the moles of HF back to grams using its molar mass of 20.01 g/mol. Multiplying 0.7676 mol by the molar mass gives us 15.358 g of HF. Therefore, the correct answer is option C: 16.7 g.