Procedure
Follow these steps To determine the constituents and amount of alkalinity in the supplied water sample.
1. Pipette out 20 ml of water sample is into a clean and dry conical flask.
2. Fill the burette with ….N sulphuric acid after rinsing, and note down the initial reading by seeing
lower
meniscus.
3. Add 2-3 drops of phenolphthalein indicator to the water sample taken in conical flask and shake well
before
titrating the ….N H2SO4.
4. At the end point pink color disappears (Fig. 1), note the reading of burette as final reading for
P-alkalinity.
5. To the same solution (solution of step 4) add 2-3 drops of methyl orange indicator and shake well
before
titration. Now titrate this solution against the ….N H2SO4 and the titration is continued until the color of
the solution becomes orange (Fig. 1). The burette reading at this point is noted as final reading for
M-alkalinity.
6. The titration is repeated for concordant value.
Safety Precautions:
1. Clamp the burette perfectly in the vertically, so that it is easy to
read the scale properly.
2. Before use rinse the burette thoroughly, while filling the burette no air bubble should be present in the
burette and dispense off working solution from the burette.
3. Remove funnel after filling burette up to mark zero. Read the lower meniscus of the burette.
4. Add same number of drops (vol.) of indicator in each titration.
5. To get better visibility of color change at the end point use filter paper below the conical flask.
6. During titration conical flask should be stirred continuously and correctly observe the end point.
.