Define some Precautions for Measurement of pH?
1. Never touch the membrane of the glass electrode with anything else except soft tissue paper since it is fragile and is easily ruined if scratched or bumped.
2. The electrodes must not be removed from the solution unless the selector switch is at zero.
3. Never dip the glass electrode in a solution with a dehydrating action.
4. For basic solutions with pH more than 11, glass electrodes of special composition are required to avoid interference due to sodium ion.
5. The glass electrode may be covered with a sleeve to save it from jerks.