D) What limitations does using universal indicator paper have compared to the PH meter?

PH - It is a measurement of Acid and alkali concentration in water. Normal water pH is 7. Above 7 value is alkalic and below 7 is acidic.

In a water tank, that is in a Clarifier or Clarifloculator pH is measured with a Ph measuring scale. The principle is that it is a scale measured from 0 to 15. When we lower the scale slowly into water the number started invissible to read in particular time .

Then raise slowly to see the reading . And that no is the pH of stored water. Practically to remove turbidity we are adding lime/ alum solution as coagulant.

If pH found more in water ex-9 ,alum solution addition to tank will be increased slightly. By trial and error method both solution supplay is controlled. With Litmus paper also can be used to know the pH .

Take small amount of water in test tube add pH indicator solution, and dip the Litmus paper and match with the given colour to know the correct pH value. Frequent test we have to use indicator solutition . But in scale even though a very minute change depends on eye sight is practically used in a water treatment plant.

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