Sulphuric Acid (0.5 M)
Molecular formula: H2SO4
Molecular weight: 98.08
Preparation: Add slowly, with stirring, 27 mL of sulphuric acid to about 1000 mL of water, and allow to cool 25°C.
Standardization: Weigh accurately about 1.5 g of anhydrous sodium carbonate, previously heated at about 270 ºC for 1 hour. Dissolve it in 100 mL of water and add 0.1 mL of methyl red solution. Add the sulphuric acid slowly from a burette, with constant stirring, until the solution becomes faintly pink. Heat the solution to boil, cool, and continue the titration. Heat again to boil and titrate further as necessary until the faint pink color is no longer affected by continued boiling.
Na2CO3 + H2SO4 → Na2SO4 + H2CO3
H2CO3 → H2O + CO2↑
1 mole of H2SO4 ≅ 1 mole of anhydrous sodium carbonate
1000 mL of 1M H2SO4 ≅ 105.99 g of Na2CO3
1 mL of 0.5 M H2SO4 ≅ 0.05299 g of Na2CO3
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