Summary: The video outlines an old-fashioned synthesis of oxalic acid dihydrate from granulated sugar by oxidizing sucrose with concentrated nitric acid. Key steps: combine 10 g sugar with 50 mL 68% HNO3 in a 250 mL flask, swirl to dissolve, gently heat to about 70°C; observe yellow color and NO2 evolution as the reaction starts; maintain strong ventilation. After about 10 minutes, switch off the hot plate and allow the mixture to boil and evaporate while maintaining reaction, until about 30 mL remain; transfer to a beaker for faster evaporation, then return to heat and reduce to ~15 mL. Continue to evolve NO2 and reduce until ~10 mL remains. Cool slowly to crystallize, filter, and dry to obtain about 4.8 g of oxalic acid dihydrate (≈65% yield). Purification can be done by recrystallization from hot water or dehydration at 120°C to give anhydrous oxalic acid. Safety: nitrogen dioxide is highly toxic; use strong ventilation.
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