Question

1191 kg of acetylsalicylic acid (in kg ) can actually be produced by your group, the theoreticka yield 2165 kg. (the group cna yoeld 55%) Will the substance yield a positive test for the phenol functional group or negative? would its melting point be broad 105-140, 136-164, or 132-136? what does this indicate about purity?

Answer 1

le Page Porcont yield of acetylsalicylic acid: 55%. Reaction : CooL RT Salicylic acid + he thotham + H₂PO4 1 Acetic anhydride coon To y lo + ch doh Acetic acid Aspirin Griven Yield of product = 1191 kg. Theoretical yield = 2165 kg practical yela . Yield - Theoretical field 100 2165 55.01 % So here we get only 55.01 4. aspirin product therefore an unreacted sally acid acetic anhydride remains present in the blask. Due to unreacted salicylic acid the substance gives positive test The collected aspirin will be tested for its Ipurity using Feel. salicylic acid contains a phenolic group but acetyl salicylic acid does not. Thorefore if you add fecly to an aspirin sample, you get a purple colour, it means that there is still some salicylic acid present 4 sample is impure

Date Page Impure substance + Fech Purple colour. gives purple colour, when Therefore reacted impure with sample tecla Standard melting point of Aspirin = 135c Now given product contains impurities. When impurities are present then the compound shows less melting point than standard melting I point. ie The presence of impurity in a substance results in a lowering of melting point due to a process called melting point depression Therefore above product would be meted at broad between 105 -140 c so it is impure substance.