Question

1. In synthesizing Aspirin, acetylsalicylic acid, you will react 2.0 g of salicylic acid with 5 mL of acetic anhydride (d=1.08 g/mL). Write the balanced chemical equation to describe this transformation. Determine your limiting reactant and calculate the theoretical yield of your product.

2. What precautionary measures must you take in handling acetic anhydride and concentrated sulfuric acid (conc. H2SO4 is used as a catalyst in this synthesis)?

Answer 1

C7H6O3 + C4H6O3 → C9H8O4 + CH3COOH

no of moles of salicylic acid   = W/G.M.Wt

                                                = 2/138 = 0.0145 moles

mass of acetic anhydride       = volume * density

                                               = 5*1.08   = 5.4g

no of moles of acetic anhydride = W/G.M.Wt

                                                   = 5.4/102   = 0.053 moles

1 mole of acetic anhydride react with 1 mole of salicylic acid

0.053 moles of acetic anhydride with 0.053 moles of salicylic acid

                 salicylic acid is limiting reactant

1 mole of salicylic acid react with acetic anhydride to gives 1 mole of aspirine

0.0145moles of salicylic acid react with acetic anhydride to gives 0.0145 moles of aspirine

      mass of aspirine = no of moles * gram molar mass

                                  = 0.0145*180   = 2.61g

theoritical yield of aspirine = 2.61g

2. Avoide ingestion and skin contact. work in a hood and plastic -work with gloves and protection glasses avoid splashing -avoid contact with eyes, skins, clothers avoid inhalation and ingestion.