NOTES ON TITRATION I. LIN Fukien Christian University, Foochow, China
The removal of air bubbles in the tip of a Mohr buret is sometimes troublesome. The quick drainage method commonly used is not efficient, as the air bubble has a tendency to rise up in spite of the down-flow of the liquid. Advantage may be taken of the fact that if the tip is turned upward the gas bubble will, by its own nature, escape with the help of the flow of a very little liquid. For quick titration, provision is usually made to reserve some of the original solution in a separate beaker to he added when the endpoint is just passed. We find that a glass tube closed with rubber and pinch clamp might serve as a stirring rod and a reservoir for liquid which can be drained out a t the endpoint. This has the advantage of being quick, as rinsing can be done by sucking the final solution up into the tube, and accurate, as it eliminates the possible splattering in transferring.
