Question

In: Chemistry

Assume all of the ionized aspirin remains in the buffer solution and all of the un-ionized...

Assume all of the ionized aspirin remains in the buffer solution and all of the un-ionized aspirin goes into the ethyl acetate, what is the molarity of the aspirin in the ethyl acetate at pH 2.0 and pH 8.0?

Did the spots observed for aspirin depend on the pH for the aqueous phase? Why or why not?

Did the spots observed for 3-aminophenol depend on the pH of the aqueous phase? Why or why not?

Did the spots observed for acetaminophen depend on the pH of the aqueous phase? Why or why not?

Solutions

Expert Solution

At pH =2

The pKa of aspirin is 3.49

pH = pKa + log [Base] / [Acid]

pH = pKa + log [Ionized] / [Unionized]

2 = 3.49 +  log [Ionized] / [Unionized]

log [Ionized] / [Unionized] = -1.49

[Ionized] / [Unionized] = 0.0323 /1

Total = 1 + 0.0323 = 1.0323 mol

[Un Ionized] = (1 / 1.0323 ) x 100 = 96.87 %

96.87% is present in ethyl acetate.

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At pH = 8

The pKa of aspirin is 3.49

pH = pKa + log [Base] / [Acid]

pH = pKa + log [Ionized] / [Unionized]

8 = 3.49 +  log [Ionized] / [Unionized]

log [Ionized] / [Unionized] = 4.51

[Ionized] / [Unionized] = 32359.36

Total = 1 + 32359.36 = 32360.36 mol

[Un Ionized] = (1 / 32360.36 ) x 100 = 0.0031 %

0.0031% is present in ethyl acetate.

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Yes. Ionization of aspirin depends on the pH of the aqueous phase.

Yes. Ionization of 3-aminophenol depends on the pH of the aqueous phase.

Yes. Ionization of acetaminophen depends on the pH of the aqueous phase.

queen_honey_blossom answered 1 year ago
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