How to adjust the pH of cholindihydrogen phosphate solution with phosphoric acid to 4.0, 4.5, 5.0, and 5.5?

 

cholindihydrogenphosphate is a type of ionic liquid with the following formula:

[ce] HO(CH2)2N(CH3)3^+ [/ce] [ce] H2PO4^- [/ce]

Can I calculate it using the Henderson-Hasselbalch equation?

Edited December 14, 200817 yr by lightyear

you're gonna need some pKa data, i suspect

You are going to need pKa data measured in that ionic liquid too.

Good luck finding any.

You are going to need pKa data measured in that ionic liquid too.

Good luck finding any.

 

nah it's a solution of the ionic liquid. I think that as long as it's fairly dilute we should be OK to only consider the pKa in water

Rereading the question I see that no solvent is specified. Could be in horse urine for all we know.

If it is a dilute solution in water then you can assume that the quaternium salt is a strong base then you only need to know the acidity constants for the phosphoric acid/ phosphate system

I think it's safe to assume this question was asked by a biologist. Only a biologist would leave so many vital parts of the question out.

there is no pKa data of the ionic liquid i mentioned before.

80 g/L solution of this ionic liquid in water has the pH of 5.0.

molar mass 201.16 g/mol

can I calculate the acid volume needed? Is titration the only solution?