pH of water

OBJECTIVE
To determine the pH of the given water sample.

PRINCIPLE
At given temperature the intensity of the acidic or basic character of the sample is indicated by pH or hydrogen ion activity. The activity of H+ ions is determined by pH meter.

INTERFERENCE:
At higher pH values, the members become somewhat sensitive to sodium and other alkali ions. Also temperature affects the pH measurement.

APPARATUS
pH meter :A pH meter is an electronic instrument used to measure the pH (acidity or basicity) of a liquid (though special probes are sometimes used to measure the pH of semi-solid substances, such as cheese). A typical pH meter consists of a special measuring probe (a glass electrode) connected to an electronic meter that measures and displays the pH reading.

PROCEDURE
1) Rinse the electrode with distilled water.
2) Standardize the instrument using buffer solution.
3) Rinse the electrode with distilled water.
4) Immerse the electrode in the sample.
5) Take the reading when it becomes stable.


RESULTS
The following values were observed:

Sample No. pH
1. 7.32
2. 7.19
3. 7.39
4. 7.46

The pH values don’t show any marked departure from normal.
By-Riddhi singh