Question

Sample of impure magnesium is reacted with dilute sulphuric acid to give the respective salt and hydrogen. If 1 g. of the impure sample gave 298.6 cc. of hydrogen at s.t.p. Calculate the % purity of the sample. [Mg = 24, H = 1].

August 2, 2024

Answer

Mg + H₂SO₄ → MgSO₄ + H₂

22400 cc of H₂ is produced from 24 g of pure magnesium

∴ 298.6 cc. of H₂ is produced from $24\over 22400$ × 298.6

= 0.3199 g of pure magnesium

∴ Percentage Purity = 0.3199 × 100 = 31.99 %

Hence, the % purity of the sample is 31.99 %

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