Timeline for pH and degree of dissociation of drugs
Current License: CC BY-SA 4.0
12 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Mar 9, 2023 at 10:31 | answer | added | Poutnik | timeline score: 1 | |
| Mar 9, 2023 at 9:58 | comment | added | Luckenberg | Let us continue this discussion in chat. | |
| Mar 8, 2023 at 22:22 | comment | added | Poutnik | As Ka1=[H+][Asp-]/[HAsp] and Ka2=[H+]]A-]/[HA] then for your supposed reaction between aspirin and acetate: K=[Asp-][HA]/([HAsp][A-]=Ka1/[H+]. [H+]/Ka2 = Ka1/Ka2. | |
| Mar 8, 2023 at 18:21 | comment | added | Luckenberg | @Poutnik so you mean that, in the case of buffer, the pH of the solution determines the degree of dissociation, so no reaction Is needed to be considered to evaluate the degree of dissociation. Instead, in the case of bicarbonate, It Is the solute (aspirin) that has the upper hand, so It reacts with bicarbonate and this affects the degree of ionization of aspirin. The consequent pH lowering has no effect on the degree of ionization (?). | |
| Mar 8, 2023 at 14:43 | comment | added | Poutnik | It depends what has the "upper hand", if the solute presence affects/determines pH or if pH affects/determines solute behavior. In our case, the PH buffer and therefore pH has the upper hand. | |
| Mar 8, 2023 at 13:40 | comment | added | Luckenberg | @Poutnik so Is It the pH of the solution that determines the degree of dissociation, and not directly the reaction between aspirin and acetate? Consequently, is the same also true in the case of bicarbonate? That is, is it the final pH, after the reaction between aspirin and bicarbonate, that determines the degree of dissociation of the aspirin itself, and not the reaction itself? | |
| Mar 8, 2023 at 13:00 | comment | added | Poutnik | The proton exchange between aspiring and acetic acid respective forms is just an equilibrium dependent of the 2 dissociation equilibrii. The pH given by the acetic buffer ( in excess wrt aspirin) determines [A-]/[HA] ratios for both. It is like K1 = x.y1/z1 and K2 = x . y2/z2, where x = [H+]. | |
| Mar 8, 2023 at 11:58 | comment | added | Luckenberg | pH=pKa, so [CH3COOH]=[CH3COO-]=0,5 M for example. About aspirin, every quantity. I think that this Isn't much important (?), I Just wanted to know the base principle about what i wrote. | |
| Mar 8, 2023 at 11:04 | comment | added | Maurice | How much acetic acid, sodium acetate and aspirin do you dissolve in your water ? | |
| Mar 8, 2023 at 10:14 | history | edited | Luckenberg | CC BY-SA 4.0 |
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| Mar 7, 2023 at 21:37 | history | edited | Luckenberg | CC BY-SA 4.0 |
added 2 characters in body
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| Mar 7, 2023 at 20:04 | history | asked | Luckenberg | CC BY-SA 4.0 |