Describe and explain the possible effect on your results of the following experi

Question

Describe and explain the possible effect on your results of the following experimental errors or variations. In each case specify the component(s) whose percentage(s) would be too high or too low. (a) After adding the dichloromethane to Panecetin, you didn't stir the mixture long enough. (b) During the NaOH extraction, you failed to mix the aqueous and organic layers thoroughly. (c) You mistakenly extracted the dicholormethane solution with 1 M HCl rather than 1 M NaOH. (d) Instead of using pH paper, you neutralized the NaOH solution to pH 7 using litmus paper.

Explanation / Answer

(a) After adding dichloromethane to Panacetin, you didn't stir the mixture long enough then the percentage concentration of aceanilide and aspirin would be more and the percentage of starch would be less and the final percentages would be low.

(b)The acid will be soluble in the ether and the aqueous solution. The reason you're adding aqueous NaOH and not just water is to neutralize the acid. When you neutralize the acid you're placing a charge on the molecule and increasing the solubility in the aqueous layer. If the NaOH was not thoroughly mixed the acid would remain somewhat soluble in the ether and the extraction would be less efficient.

(c) the 5% HCl that would protonate the aspirin and keep it in the organic phase soln making the aspirin acetylsalicylic acid. So i guess thats why u used bicarbonate (to precipitate the base form = acetylsalicylate)

(d) At ph7 the NaOH wouldnt be able to act as a bass and extract a proton from the aspirin because at ph7 it would be protonated itself, so it wouldnt be able to react with the aspirin

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