Setting Up the Titration (Steps 5 and 6 of the procedure)

You will check two burets out from the stockroom. Label one "acid" and the other "base". Make sure only acid solution goes in the acid buret and base in the base buret. Clamp the burets into the buret clamp when you are not using them. (See picture below left.) When you clamp the burets in, make sure they are veritcal. The picture below right shows a buret being clamped in crooked at first, but then corrected to be clamped in vertically.

The clearly labelled acid and base burets clamped vertically into the buret clamp.

Clamping the buret into the buret clamp. Notice that the buret goes in crooked at first, but is then corrected so that it is vertical.

Before filling and using the burets, you should thoroughly clean the burets so that liquid will not cling to the sides as the burets are drained during the titration experiment (since this would introduce error into your volume measurements). The teflon stopcock of the buret should first be removed from the end and the inside of the buret barrel scrubbed with detergent and a buret brush. The buret should then be rinsed thoroughly with tap water to remove all traces of detergent and then rinsed thoroughly with distilled water. (These steps are illustrated below).

A dirty buret. Notice the liquid clinging to the sides. This will introduce error into your volume measurements. Liquid should drain cleanly from the sides if the inside of the buret is clean.

The teflon stopcock should pull out easily from the end of the buret. Remove the stopcock before cleaning the buret.

Scrub out the barrel of the buret with detergent and a buret brush.

Rinse thoroughly with tap water, then distilled water.

Before filling the burets they should be rinsed out once more, but now with the solution you plan on filling the buret with. First put the teflon stopcock back in with the valve shut. Then pour about 10 mL of dilute acid or base solution into the buret, tilt the buret on its side, and rotate the buret so that the solution rinses the sides. Once the sides are thoroughly rinsed, right the buret and open the stopcock valve to let all of the solution drain through the stopcock tip. (See pictures below.)

Put the teflon stopcock back in with the valve closed and pour about 10 mL of the solution you want to fill the buret with in to the buret.

Tilt the buret on its side and wash down the walls by rotating the buret. Then right the buret and let all of the solution drain out through the stopcock tip.

Now fill the buret with the dilute acid or base solution until the liquid level is close to the top of the measuring range. Then open the stopcock valve and let a few mL of solution run through until all air bubbles are purged from the tip. Close the stopcock valve and read the initial volume on the buret (for this first titration we will only read the initial volume of the base). You will then (finally!!) be ready to start the first titration.

Open the stopcock and let a few mL of solution flow through until all air bubbles are purged from the tip.

Then read the initial volume on the buret (do only for the base buret in the first titration). A black line on a white piece of paper held behind the buret will darken the meniscus and make it a little easier to read the volume. I would read this volume as 3.42 mL, do you agree with that?