Question

Calculate the mass percent (w/w) of sulphuric acid in a solution prepared by dissolving 4 g of sulphur trioxide in a 100 ml sulphuric acid solution containing 80 mass percent (w/w) of H2SO4 and having a density of 1.96 g/ml. (molecular weight of H2SO4 = 98). Take reaction SO3 + H2O $\rightarrow$ H2SO4

• A. 80.8%
• B. 84%
• C. 41.65%
• D. None of these

Answer 1

Answer: (A)

80.8%

Answer 2

(1)

Mass of H2SO4 formed by 4g SO3 = 4.9 g

Mass % of H2 SO4 $= \frac{100 \times 1.96 \times 0.8 + 4.9}{100 \times 1.96 + 4} = 80.8\%$