ph concept

[rachel liu 3k]

please quote my question so i get a notification, thanks in advance!

i know there is something wrong with my thought process, but i cannot figure it out. my thought process is that if a base is weaker, less oh- will be dissociated out. taking the -log of that smaller number will result in a smaller pOH, and therefore a higher pH.

i know i'm supposed to be getting a less basic solution, or a lower pH and a higher pOH, but i cannot seem to figure out what is wrong with this statement. hope you can help, thanks!

[Sebastian Lee 1L]

please quote my question so i get a notification, thanks in advance!

i know there is something wrong with my thought process, but i cannot figure it out. my thought process is that if a base is weaker, less oh- will be dissociated out. taking the -log of that smaller number will result in a smaller pOH, and therefore a higher pH.

i know i'm supposed to be getting a less basic solution, or a lower pH and a higher pOH, but i cannot seem to figure out what is wrong with this statement. hope you can help, thanks!

You're right in that less OH^- will be dissociated in a weaker base. However, if you take the negative log of the small number you will actually get a larger value for pOH. Log functions make small values big and large values small. For example, if you had a concentration of OH^- that was 10^-2 mol/L, taking the negative log gives you 2. If you had an even smaller [OH^-] of 10^-5 mol/L, then you would get an even larger pOH: 5. Therefore, a weaker base with a smaller OH^- concentration gives you a larger pOH value and a smaller pH. Good luck on the final! :)

[vpena_1I]

taking the -log of a smaller [OH-] gives you a higher pOH, making the pH smaller.

[Eugene Chung 3F]

please quote my question so i get a notification, thanks in advance!

i know there is something wrong with my thought process, but i cannot figure it out. my thought process is that if a base is weaker, less oh- will be dissociated out. taking the -log of that smaller number will result in a smaller pOH, and therefore a higher pH.

i know i'm supposed to be getting a less basic solution, or a lower pH and a higher pOH, but i cannot seem to figure out what is wrong with this statement. hope you can help, thanks!

If a base is weaker, less oh- will be generated. Since pOH is -log[OH-], smaller, low [OH-] will generate higher number. (ex: if [OH-]= 0.1, -log of that is 1. if [OH-] is 0.01, -log of that is 2, so lower [OH-]= higher pOH). Since pH = 14-pOH, the higher the pOH, the lower the pH. This makes sense since the weaker the base, the lower the pH will be.

[rachel liu 3k]

please quote my question so i get a notification, thanks in advance!

i know there is something wrong with my thought process, but i cannot figure it out. my thought process is that if a base is weaker, less oh- will be dissociated out. taking the -log of that smaller number will result in a smaller pOH, and therefore a higher pH.

i know i'm supposed to be getting a less basic solution, or a lower pH and a higher pOH, but i cannot seem to figure out what is wrong with this statement. hope you can help, thanks!

If a base is weaker, less oh- will be generated. Since pOH is -log[OH-], smaller, low [OH-] will generate higher number. (ex: if [OH-]= 0.1, -log of that is 1. if [OH-] is 0.01, -log of that is 2, so lower [OH-]= higher pOH). Since pH = 14-pOH, the higher the pOH, the lower the pH. This makes sense since the weaker the base, the lower the pH will be.

This was super helpful! I think I was doing something wrong with my calculator because I thought the trend was higher OH concentration = higher pOH.

[ramiro_romero]

please quote my question so i get a notification, thanks in advance!

i know there is something wrong with my thought process, but i cannot figure it out. my thought process is that if a base is weaker, less oh- will be dissociated out. taking the -log of that smaller number will result in a smaller pOH, and therefore a higher pH.

i know i'm supposed to be getting a less basic solution, or a lower pH and a higher pOH, but i cannot seem to figure out what is wrong with this statement. hope you can help, thanks!

A weaker base will not fully dissociate in solution, meaning a higher pOH and a lower pH. when pH is less than 7, (relatively low pH) then you know it is a base.