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jkh4
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please help! questions on pKa of Phenol
Hi, I have some questions regarding the pKa of Phenol lab that I am working on right now.
1) What would cause the absorbance curves to not go through the isosbestic point?
For this one, I know that isosbestic point is not pH dependent so pH won't affect, and definitely true if there is a change in the total concentration of phenol or ratio of phenol to phenolate. But what about a change in the position of the equilibrium?
2) The wavelength of the transition depends on the exact energy difference between either π or n orbitals and the π* orbitals -- in other words, the HOMO-LUMO gap or the n-LUMO gap. When the energy gap becomes smaller, for example by increasing the size of the conjugated system, the absorbance wavelength increases. The question is what kind of factors affect this energy gap (HOMO-LUMO gap or the n-LUMO gap) for aromatic compounds.
3) Why was the rinsing of glassware with acetone not allowed in this experiment?
I know that acetone is UV active so it will give interences also acetone will dissolve the phenol, but will the acetone react with phenol?
Thank you so much for your help =)
Hi, I have some questions regarding the pKa of Phenol lab that I am working on right now.
1) What would cause the absorbance curves to not go through the isosbestic point?
For this one, I know that isosbestic point is not pH dependent so pH won't affect, and definitely true if there is a change in the total concentration of phenol or ratio of phenol to phenolate. But what about a change in the position of the equilibrium?
2) The wavelength of the transition depends on the exact energy difference between either π or n orbitals and the π* orbitals -- in other words, the HOMO-LUMO gap or the n-LUMO gap. When the energy gap becomes smaller, for example by increasing the size of the conjugated system, the absorbance wavelength increases. The question is what kind of factors affect this energy gap (HOMO-LUMO gap or the n-LUMO gap) for aromatic compounds.
3) Why was the rinsing of glassware with acetone not allowed in this experiment?
I know that acetone is UV active so it will give interences also acetone will dissolve the phenol, but will the acetone react with phenol?
Thank you so much for your help =)
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