In acid-base titration, why is acid usually filled into the burette but not base?

Answer 1

1) Bases like NaOH or KOH attack glass, so you don't want to corrode your burette with time.
2) Sometimes basic solutions form crystals on the burette tip and the hole becomes clogged. Crystal formation is directly proportional to base concentration.
3) Mixing acid with base or water, you get an exothermic reaction (heat generation). So, it is better (safer) to place acid (drop by drop) on water or base than placing them on a lot of acid.

You don't need to place the titrant in the burette and the analyte in the flask (beaker, erlenmeyer, etc.). You can put an exact amount of titrant (measured with a pipette) in the flask and add your analyte from the burette (for math purposes it is indifferent whether the titrant is above or below, but for practical purposes it is convenient to place the acid in the burette).
If your basic solution is a very dilute one (so the risks of points 1) and 2) are minimal) and your indicator is phenolphthalein, you could place the base in the burette because it is easier to see the color change from colorless to pink than viceversa.

Answer 2

It is not always done this way.

There is no reason why a base cannot be used in the burette.

Here is a universtity protocol (from the University of Southern Maine) in which the base is used in the burette. The prodedure is a two parter. 1. The solution of 0.1M NaOH in the burette is standardized against an acid 2. This standardized NaOH solution is used to titrate an unknown acid and to find its molarity.
http://www.usm.maine.edu/chy/manuals/114/text/ABTiProc.pdf#search=%22titration%20procedure%22

Answer 3

For the love of God people...

Titration is used to determine the concentration of a substance (analyte) with the help of a standard solution (titrant).
The titrant is always in the burette so that you can calculate the concentration of the analyte by measuring the volume of added titrant.

So when your analyte is an acid you need a base as titrant and that's what will be in the burette (despite problems such as OH- reacting with glass, specially treated distilled water for making the titrant solution so that CO2 is minimized etc).

Answer 4

Now don't quote me on this, but it may be because of the indicator. When I did titration in chemistry, we had the base below the buret with a colored indicator that turns clear when the acid is added and the proper pH is met. I think that if it were the other way around, it would not turn color until you've added too much base.
Something along those lines.

Answer 5

to neutralize the solution, or to adjust a certain pH in which an appropriate indicator gives a color change. neutralization gives a definite and known yield, avoiding some side reaction.. therefore, acid - base reaction is used in titration because the reaction is definite (straight, avoiding other product that may yield) and gives a definite pH at the equivalence point in which an appropriate indicator may give a color change.

Answer 6

Bases, (NaOH, KOH etc.), attack glass. The reaction is slow and for most purposes the effect is insignificant. But, the reaction will corrode the joint of a ground glass stopper on a burette causing it to leak.

Answer 7

because, bases form a precipitate, n end up in d mouth of the tube and the flow would be slow.. acids are used in burettes purely for convenience.

Answer 8

<>Ooooooohhh, it's been a loooong time but, I believe it's because adding the acid to the base will less likely result in a dangerous reaction that might harm the chemist (or something to that effect!).