To determine the Acidify of given sample of water

To determine the Acidify of given sample of water

METHOD DISCUSSION:

Acidity is not specified pollutant, and it 1s a measure of the effects of combination of substances and conditions in water. I may be defined as the power of water to neutralize hydroxyl ions and is expressed in terms of calcium carbonate

Acidity is usually caused by the presence of the free carbon dioxide minerals acids such as Sulphuric, and weekly dissociated acids. Iron and aluminum salts hydrolyze in water to release mineral acidity. release mineral acidity. Surface water and ground water attain acidity from humic acid from industrial wastes such as pickIing liquors, and from acid mine drainage

PRINCIPLE:

Acidity is usually determined by titration with 0.2 N of sodium hydroxide solution. The amount of sodium hydroxide required for the sample (having pH less than 4.5) to reach pH 4.5 ( methyl orange end point ) is a measure of the “ Mineral acidity” and he amount to reach pH 8.3 (phenolphthalein end point ) is a measure of the total acidity. Color change titrimetric method or potentiometric titration may be adopted for the determination of acidity/

REAGENIS:

1. Methyl orange indicator solution:
   

Dissolve 50mg methyl orange powder in distilled water and dilute to 100 ml.

1. Phenolphthalein indicator Solution:
   

Dissolve 0.5g dissolved in 50ml ethanol

1. Sodium hydroxide solution, 0.02N:
   

Prepare Sodium hydroxide solution by dissolving 40g NaOH in distilled water and diluting to 100m. Standardize it against standard N-Sulphuric acid (prepared for alkalinity determination). Dilute appropriate volume of the N-NaOlH solution (about 20m) to 1000ml to give a 0.02N solution. 1.0 ml of exactly 002N-NaOH= 1mg CaCo3

ROCEDURE

Methyl Orange Acidity

1. Place 50 ml or suitable aliquot of the sample (required less than 25ml of titrant) in a 250ml conical 1lask.
   
2. Add 2 drops of methyl orange indicator solution and
   
3. Titrate with 0.02N NaOH solution (lo pl1 4.3) to faint orange colour.
   

Total acidity (using phenolphthalein) at room temperature:

1. Place 50 mi or suitable aliquot of the sample required less than 25ml of titrant) in a 250ml conical flask.
   
2. Add 3 drops phenolphthalein indicator.
   
3. Titrate with 0.02 N-NaoH s0lutton to the appearance of taint pink colour (to pH 8.3).
   

Note: If the Sample is colored, titration may conveniently be performed, potentiometrically to the required pH values

CALCULATIONS:

If the normality of Sodium hydroxide solution is exactly 0.02 N,

While reporting results, state the indicator used and the temperature at which the titration has been performed.

Interpretation of the results:

As Discussed earlier, the Methyl Orange acidity value indicates the mineral acidity, and, the total acidity (using phenolphthalein indicator) is the sum of both mineral acidity and carbon oxide acidity. However, in the absence of mineral acidity, total acidity is only the CO2 acidity and 1s the case with most of the samples

There is no specific limit for acidity but it is indirectly controlled by the limits on pH value.

Excessive acidity is determine and should be neutralized to mitigate corrosion. Mineral acid

pollution in rivers and Streams can be quit detrimental to fish and other aquatic life.

OBSERVATION: