Just want to confirm something about tiration (1 Viewer)

[hydrobiont]

Do we fill the burette with a solution of unknown concentration or known concentration?

Some text books say this and some say the opposite.
I'm so confused.

 

[Tuna]

You fill the burette with a base (except for back-titration which you don't need to know)

For simple titration, you will be titrating an unknown concentration base with a known concentration and volume of HCl.

2. After finding the end-point, you will use you known base concentration and volume (i.e to work out your molar). To tritate against an unknown acid, in this case acetic for the syllabus.

 

[Dreamerish*~]

You fill the burette with a base

You fill the burette with a solution, the concentration of which you do know. Whether this is acid or base depends on whether it's the concentration of the acid you know, or whether it's the concentration of the base you know.

It's not always base in the burette. In the RACI Titration Competition we used acid in the burette and base in the conical flask.

 

[sando]

i thought it doesnt matter which one, but u just fill it with the liquid u know what it is

 

[PLooB]

Dreamerish is right. You fill the burette with the solution of known concentration. I think this is done so you can measure how much of the known solution is needed to change colour.

 

[Dreamerish*~]

I always thought it didn't matter which was which, as long as you rinsed the equipment with the respective solutions to prevent further dilution, and you knew the concentration of 1 of the solutions and the volumes of both. After all, all simple titration calculations are solved using the formula

c₁v₁ = c₂v₂

Tell me if i'm wrong though =)

C₁V₁ = C₂V₂ works only if the molar ratio of acid to base is 1:1.

If the ratio is a:b, then your formula would read:

C₁V₁/C₂V₂ = a/b

("a" being ₁ and "b" being ₂)

 

[sikeveo]

You fill the burette with a solution, the concentration of which you do know. Whether this is acid or base depends on whether it's the concentration of the acid you know, or whether it's the concentration of the base you know.

It's not always base in the burette. In the RACI Titration Competition we used acid in the burette and base in the conical flask.

Are you sure? You're not supposed to put acid in the burretes as it corrodes the inside.

 

[Dreamerish*~]

Are you sure? You're not supposed to put acid in the burretes as it corrodes the inside.

I'm sure.

Burettes are made from glass, so if you can't use acids in burettes, you can't use them in pipettes or conical flasks either - unless you're talking about the tap thing at the bottom. But again, we had acid in the burette at the titration comp.

 

[sando]

the acids they give you aren't going to corrode the plastic away

 

[insert-username]

When we did the prac we had the unknown solution in the burette, not the known one, and that was following the textbook. Perhaps it's just more accurate to pipette in the unknown rather than the known, but I'm not really sure if it matter either way.


I_F

 

[silent_albert]

hi....
dont kno if this is going to help but everyone else is saying both things.... we hav just done this experiment in class and we had HCl of unknown concentration in the burette adding it to a conical flask of sodium carbonate of which we had measured out and mixed to be the primary standard.
so for us the burette (which is made of glass and therefore cant be corroded) held the acid of unknown concentration and the primary standard base was in the flask

so really i dont think it matters which way u do it because either way u should know the volumes of each liquid once they are neutral

 

[Dreamerish*~]

hi....
dont kno if this is going to help but everyone else is saying both things.... we hav just done this experiment in class and we had HCl of unknown concentration in the burette adding it to a conical flask of sodium carbonate of which we had measured out and mixed to be the primary standard.
so for us the burette (which is made of glass and therefore cant be corroded) held the acid of unknown concentration and the primary standard base was in the flask

It doesn't actually matter because you end up with the same information - the volume used for each solution, and the concentration of one of them.

Technically though, the solution of known concentration goes in the burette.

 

[Riviet]

My chemistry teacher said that doing it either way will yield the same results, but the "old" or "classical" way of doing it was with the known concentration of solution in the burette. He said that there was even a specific way of letting out the solution from the burette, which was to put your left hand around the back of retort stand to turn the knob, while holding the conical flask with your right hand about 1cm above the white ceramic tile, so you could swirl the solution around after every few drops of the solution. That happens to be also why we use a conical flask, not a beaker, since the tight opening means the solution doesn't spill out so easiliy when you swirl the solution around.

 

[babywwq]

either way

but i perfer add known acid in bur