Exp011GSreport

Sulfuric and Phosphoric acid's role and difference in exp 011
In [|Experiment 011] an attempt is made to covert [|adrenaline] to [|dopal] using concentrated sulfuric acid.

The [|H2SO4 (sulfuric acid)] dehydrated the adrenaline. H2SO4 acts as an acid and removes the water.

Sulfuric acid is more acidic than [|phosphoric acid] because phosphoric acid's [|pKa] values are greater than those of sulfuric acid.

Phosphoric acid (H3PO4)

Sulfuric acid (H2SO4)

Phosphoric acid's pKa values are [|2.148, 7.190, and 12.350], where as sulfuric acid's pKa values are [|1.99 and -3.0]. This suggests that sulfuric acid's most acidic proton is more acidic than phosphoric acid's most acidic proton. For example; phosphoric acid in a neutral solution would act as an strong acid and drop the total pH; however, sulfuric acid would act as a stronger acid in the same neutral solution and drop the total pH lower (more acidic).

Despite their differences in strength, they are both strong enough to dehydrate the adrenaline in this [|E-1 reaction (lec. 22 & 23)].


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