Freshmen Research Initiative
Nano Stream
Spring 2009
Burets and Titration
A buret (also spelled burette) is used to dispense known amounts of a liquid reagent in
experiments for which such precision is necessary, such as a titration experiment. Burets are
extremely precise: class A burets are accurate to ±0.01 mL.
Before you start using a buret, it needs to be properly prepared. Follow the procedure outlined
below to prepare a buret:
1. Close the stopcock, and run some DI water using a DI squirt bottle into the top of the
buret. Tilt the buret at an angle with a rocking motion to let the water rinse all of the
inside of the buret.
2. Open the stopcock, and drain out the water from the tip into the drain.
3. Repeat the above steps at least twice.
4. Close the stopcock and (using a funnel, if you prefer) pour some of the titrant in from the
top of the buret (no more than ¼ of the total buret volume). Remove the funnel.
5. Tilt the buret at an angle to rinse all the inside of the buret with titrant solution.
6. Place the buret into the clamp (DO NOT tighten the clamp too much. It may crack the
buret). Make sure the buret is perfectly vertical and stable.
7. Drain the titrant into a waste beaker. Label the temporary waste beaker.
8. Fill the buret with the titrant to the top (~50 ml). Do NOT try to aim at the 0.00 ml mark.
Just get it near the top within the marked area. Remove the funnel.
9. Place the waste beaker underneath the buret tip, and open the stopcock to let the titrant
run down to fill the buret tip. Make sure air bubbles aren’t trapped around the
stopcock. If air bubbles are present during a titration, volume readings may be in error.
If you have trouble getting air bubbles out, call your instructor or TA for help.
10. Rinse the tip of the buret with water from a wash bottle and remove any drops adhering
to the buret tip by touching on the side with a clean Kimwipe. After a minute, check for
solution on the tip to see if your buret is leaking. The tip should be clean and dry before
you take an initial volume reading.
Below is the general procedure that should be followed whenever you are performing a titration:
1. When your buret is conditioned and filled, with no air bubbles or leaks, take an initial
volume reading to two decimal places. See tips for reading the buret correctly in the next
section, below.
2. Adjust the buret height, so that the tip of the buret is slightly below the rim of the titration
flask. This will prevent the loss of titrant by splashing outside the flask.
3. Begin titrating by adding a stream of the titrant into your flask. The solution should be
delivered quickly until a couple of mL from the endpoint. Swirl the flask to evenly
distribute the titrant throughout the solution. The indicator coloration quickly dissipates
as the titrant is mixed with the solution. As the titration progresses, the observed
coloration will persist for longer periods when the flask is swirled. When the desired
coloration persists for a few (about 5) seconds, the endpoint has been reached and
the titration should be stopped. Addition of too much titrant leads to a deeper color
coloration that won’t go away, even with swirling. This means you’ve gone too far!
Technical Information – Burets
Freshmen Research Initiative
Nano Stream
Spring 2009
4. As you get nearer to the endpoint (i.e. when you start noticing that the desired color is
persisting for a couple seconds), slow down the rate at which you add your titrant to
about one drop at a time, so that you don’t overshoot the endpoint.
5. When you have titrated to your endpoint, record the final buret reading to two decimal
places.
6. When repeating the titration, try to aim for the same faint colored endpoint (i.e. an
endpoint that persists for ~5 seconds) in the replicate experiments.
A few tips for using and reading a buret:
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A 50 mL buret can be read to ±0.01 mL by extrapolating the last decimal place. Make
sure you record enough significant figures in your readings. For example: “5.2 mL” is
not the same as “5.20 mL”. This will affect the number of significant figures you report
at the end.
Read the bottom of the meniscus. Be sure
your eye is at the level of meniscus, not
above or below. Reading from an angle,
rather than straight on, results in a parallax
error.
Keep in mind that you are interested in the
Volume Change (Vfinal-Vinitial) in a
titration. Therefore, you don’t necessarily
need to refill the buret to the top to start a titration.
Technical Information – Burets