APPARATUS AND REAGENTS
1. pH meter
2. Standard buffer solution pH 4.0
3. Standard buffer solution pH 9.0
4. Deionized or distilled water
Rinse the electrodes with deionized water and dry them using a tissue. Place them in the buffer solution pH 4 and adjust the instrument to read the exact pH of the solution at the temperature of the experiment (Check pH variation of the buffer with temperature).
Rinse the electrodes and place them in the second buffer. Adjust the slope calibration to attain the reading of the second buffer. Satisfactory calibration should be done using the two buffer solution. Finally rinse the electrodes and place them in the water sample and read the Ph.
Conductivity meter with conductivity cell of constant 0.1 or 1
Check the battery by following the instructions on the meter, after connections using the appropriate leads. Adjust the temperature control to correspond with the temperature of the water. Measure the conductivity noting the cell you are using. Report conductivity in micro mhos/cm.
3. TOTAL ACIDITY AND MINERAL ACID ACIDITY
0 Phenolphthalein indicator solution. Dissolve 0.5g phenolphthalein in 100 Ml ethyl alcohol and add 50 ml distilled water. Then add 0.02N NaOH dropwise until a faint pink colour appears.
1 Methyl orange indicator solution- Dissolve 0.05 g methyl orange in 100 ml distilled water.
2 Standard sodium hydroxide solution, 0.02N – freshly prepared using distilled water which has been freshly boiled for at least 10 min to expel CO2.
Total acidity – pipette carefully without disturbing the sample, 100 ml of the water into a 250 ml conical flask. Add 3 drops of the phenolphthalein solution. Titrate over a white surface with 0.02 N NaOH to the appearance of the faint pink colour.