SAQ : SO3 is prepared by oxidizing SO2 with oxygen. How many grams of SO2 will be required to produce 40 g of SO3 ?

Question

SO₃ is prepared by oxidizing SO₂ with oxygen. How many grams of SO₂ will be required to produce 40 g of SO₃ ? [O = 16, S = 32] [Ans. 32 g]

Answer

The balanced chemical equation for the reaction of SO₂ with O₂ to form SO₃ is:

2 SO₂ + O₂ → 2 SO₃

Molar mass of SO₃ = 1 × 32  + 3 × 16 = 80

Number of moles of SO₃ = 40\over 80 = 0.5 mol

Since the molar ratio of SO₂ to SO₃ is 1:1, we need the same number of moles of SO₂ as SO₃ to react completely. Therefore, the number of moles of SO₂ required is also 0.5 mol.

Finally, we can use the molar mass of SO₂ to calculate the mass of SO₂ required:

Mass of SO₂ = 0.5 × 64 = 32 g

Therefore, 32 g of SO₂ will be required to produce 40 g of SO₃.