Titration Procedure

Standardizing a Base

Clean a buret, rinse it a few times with the base to be standardized, and then fill it.   Weigh the required amount of solid acid onto a weighing paper, and add it to an erlenmeyer flask.  Put in enough deionized water to dissolve the acid.  Then add two or three drops of indicator, in this case phenolphthalein.  Read the starting level of the base in the buret, at the bottom of the meniscus.  A white card with a black line can help to locate the bottom of the meniscus accurately.  Then open the valve, and allow the base to run into the acid.  At first you can let the base run in rapidly, until you start to detect a color change.  Then slow down, and add the base drop by drop.  Occasionally, wash down the sides of the flask with deionized water.   When one drop causes the color to change to a persistent pink color, the titration is done.  Read the ending level of the base in the buret.