PI pH cathod/anode

[pistolpete007]

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if the pi=8...and put into a solution of pH=5.....would this go toward anode or cathode....i believe it is anode but im not sure if it being in a elctrolytic cell or galvanic cell has nething to do with it...

 

[osimsDDS]

if the pi=8...and put into a solution of pH=5.....would this go toward anode or cathode....i believe it is anode but im not sure if it being in a elctrolytic cell or galvanic cell has nething to do with it...

basically if you have a pI of 8 then it is neutral at that pH...now if you put it in a solution of pH=5 then that means it has to go from 8 to 5 (think of the 8 being pH of 7 which is neutral). So if its going from neutral down its gonna be acidic which gives off H+ protons right...if for example its going from neutral up then its gonna be basic which gives off OH-...

So in any case when its acidic it gives off H+ protons so its gonna be attracted to the negative anode in a galvanic cell and in an electrolytic cell its gonna be attracted to the negative cathode...

 

[harrygt]

basically if you have a pI of 8 then it is neutral at that pH...now if you put it in a solution of pH=5 then that means it has to go from 8 to 5 (think of the 8 being pH of 7 which is neutral). So if its going from neutral down its gonna be acidic which gives off H+ protons right...if for example its going from neutral up then its gonna be basic which gives off OH-...

So in any case when its acidic it gives off H+ protons so its gonna be attracted to the negative cathode in a galvanic cell and in an electrolytic cell its gonna be attracted to the positive anode...

What is meant by PI?

 

[Mstoothlady2012]

What is meant by PI?

Isoelectric Point

 

[Mstoothlady2012]

basically if you have a pI of 8 then it is neutral at that pH...now if you put it in a solution of pH=5 then that means it has to go from 8 to 5 (think of the 8 being pH of 7 which is neutral). So if its going from neutral down its gonna be acidic which gives off H+ protons right...if for example its going from neutral up then its gonna be basic which gives off OH-...

So in any case when its acidic it gives off H+ protons so its gonna be attracted to the negative cathode in a galvanic cell and in an electrolytic cell its gonna be attracted to the positive anode...

I think you have it backwards osims

cathode is negative in electrolytic & anode is negative in galvanic

This is what I think. Since PH<PI, its going to be protonated. Which means it will have + charge & will run towards negative charge. So it will run towards cathode in electrolytic & anode in galvanic.

 

[151AND8TH]

pI = pH at which the molecules have an overall neutral charge (they would have to tell u what the pI is) -- an example of Alanine will show an overall charge of "0" when its at neutral pH and a "+1" when its at pH 1.5 and a overall "-1" when the pH is very basic ..

anyway when the overall charge of an amino acid is "0" which is when pI=pH, the amino acid is called a zwitterion

 

[TexasDent]

When you are dealing with pI and pH of amino acids you conduct the electrophoresis in an elecrolytic cell meaning that a current of charge from an outside energy source is run through it. So the (-) end is the cathode and the (+) end is the anode.

 

[dleodyddlek]

I have just cause even more confusion on myself omg..

 

[pistolpete007]

I'll try to be as simple as possible since many people already gave conceptual reasoning.

Think of PI being 8 just as that molecule having pH of 8. and now since the solution has pH5, solution works as acid and the molecule as base. Now, as a base molecule being in comparably acidic solution, it will now be protonated which will make the molecule positively charged. Now what will a positively charge molecule be attracted to? Negatively charged electrode. - we'll come back to this.

and the question is, what is the negative electrode? does it matter whether it's voltaic or electrolytic cell? well, to make it simple, electron always flow from anode(-) to cathode(+). [duh]

don't get confused whether it's electrolytic so now cathode acts anode???? what the hell is going on????

the reason for interchanged electrode is only because the direction of electron flow has been flipped from voltaic to electrolytic; ie. discharging to recharging of battery. That said, it never happens that an anode now acts as cathode but still emits electrons, no.

so back to the main question, the positively charged molecule of yours will move towards anode which is emiting electrons thus negatively charged, no matter what type of cell you have. I wish this could help. :]

the last paragrpah doesnt make too much sense to me...or im reading it wrong if pI=8 and pH=5 then it will move toward the ANODE IN GALVENIC but the CATHODE IN ANODE.....so it does matter what type of cell u have doesnt it?

 

[Mstoothlady2012]

I'll try to be as simple as possible since many people already gave conceptual reasoning.

Think of PI being 8 just as that molecule having pH of 8. and now since the solution has pH5, solution works as acid and the molecule as base. Now, as a base molecule being in comparably acidic solution, it will now be protonated which will make the molecule positively charged. Now what will a positively charge molecule be attracted to? Negatively charged electrode. - we'll come back to this.

and the question is, what is the negative electrode? does it matter whether it's voltaic or electrolytic cell? well, to make it simple, electron always flow from anode(-) to cathode(+). [duh]

don't get confused whether it's electrolytic so now cathode acts anode???? what the hell is going on????

the reason for interchanged electrode is only because the direction of electron flow has been flipped from voltaic to electrolytic; ie. discharging to recharging of battery. That said, it never happens that an anode now acts as cathode but still emits electrons, no.

so back to the main question, the positively charged molecule of yours will move towards anode which is emiting electrons thus negatively charged, no matter what type of cell you have. I wish this could help. :]

So you are saying that in both galvanic & electrolytic - anodes are always negatively charged?

 

[Mstoothlady2012]

I'll try to be as simple as possible since many people already gave conceptual reasoning.

Think of PI being 8 just as that molecule having pH of 8. and now since the solution has pH5, solution works as acid and the molecule as base. Now, as a base molecule being in comparably acidic solution, it will now be protonated which will make the molecule positively charged. Now what will a positively charge molecule be attracted to? Negatively charged electrode. - we'll come back to this.

and the question is, what is the negative electrode? does it matter whether it's voltaic or electrolytic cell? well, to make it simple, electron always flow from anode(-) to cathode(+). [duh]

don't get confused whether it's electrolytic so now cathode acts anode???? what the hell is going on????

the reason for interchanged electrode is only because the direction of electron flow has been flipped from voltaic to electrolytic; ie. discharging to recharging of battery. That said, it never happens that an anode now acts as cathode but still emits electrons, no.

so back to the main question, the positively charged molecule of yours will move towards anode which is emiting electrons thus negatively charged, no matter what type of cell you have. I wish this could help. :]

the last paragrpah doesnt make too much sense to me...or im reading it wrong if pI=8 and pH=5 then it will move toward the ANODE IN GALVENIC but the CATHODE IN ANODE.....so it does matter what type of cell u have doesnt it?

I agree with this 🙂