Physical chemical and biological properties of water
Answers
Answer:
hey mate
Explanation:Physical properties
1. Turbidity of Water
The turbidity is measured by a turbidity rod or by a turbidity meter with optical observations and is expressed as the amount of suspended matter in mg/l or parts per million (ppm).
For water, ppm and mg/l are approximately equal.
The standard unit is that which is produced by one milligram of finely divided silica (fuller’s earth) in one litre of distilled water.
2. Colour
The presence of colour in water is not objectionable from health point of view, but may spoil the colour of the clothes being washed. The standard unit of colour is that which is produced by one milligram of platinum cobalt dissolved in one litre of distilled water.
3. Taste and Odour
The extent of taste or odour present in a particular sample of water is measured by a term called odour intensity, which is related with the threshold odour or threshold odour number.
Water to be tested is therefore gradually diluted with odour free water, and the mixture at which the detection of odour by human observation is just lost, is determined. The number of times the sample is diluted represents the threshold odour number.
For public supplies, the water should generally free from odour, i.e. the threshold number should be 1 and should never exceed 3.
4. Temperature of Water
For potable water, temperature of about about clip_image002C is desirable. It should not be more than clip_image004C.
5. Specific Conductivity
The total amount of dissolved salts present in water can be easily estimated by measuring the specific conductivity of water.
Chemical Characteristics of Water
1. Total Solids and Suspended Solids
Total solids (suspended solids + dissolved solids) can be obtained by evaporating a sample of water and weighing the dry residue left and weighing the residue left on the filter paper.
The suspended solid can be found by filtering the water sample. Total permissible amount of solids in water is generally limited to 500 ppm.
2. pH value of Water
clip_image006
If clip_image008concentration increases, pH decreases and then it will be acidic.
If clip_image008[1] concentration decreases, pH increases and then it will be alkaline.
clip_image010
pH + pOH = 14
if the pH of water is more than 7, it will be alkaline and if it is less than 7, it will be acidic.
The alkalinity is caused by the presence of bicarbonate of calcium and magnesium or by the carbonates of hydroxides of sodium, potassium, calcium and magnesium.
Some, but not all of the compounds that cause alkalinity also cause hardness.
pH Measurement:
the pH value of water can be measured quickly and automatically with the help of a Potentiometer.
The pH can also be measured by indicators as given below:
Indicator pH range of indicator dye Original color Final color produced
Methyl orange 2.8 – 4.4 Red Yellow
Methyl red 4.4 – 6.2 Red Yellow
Phenol red 6.8 – 8.4 Yellow Red
Phenolphthalein 8.6 – 10.3 Yellow Red
Permissible pH value for public supplies may range between 6.6 to 8.4.
The lower value of pH may cause incrustation, sediment deposits, difficulty in chlorination.
3. Hardness of Water
Hard waters are undesirable because they may lead to greater soap consumption, scaling of boilers, causing corrosion and incrustation of pipes, making food tasteless etc.
Temporary Hardness: If bicarbonates and carbonates of calcium and magnesium are present in water, the water is render hard temporarily as this hardness can be removed to some extent by simple boiling or to full extent by adding lime to water. Such a hardness is known as temporary hardness or carbonate hardness.
Permanent Hardness: If sulphates, chlorides and nitrates of calcium or magnesium are present in water, they can not be removed at al by simple boiling and therefore, such water require special treatment for softening. Such a hardness is known as permanent hardness or non-carbonate hardness.
It is caused by sulphates, chlorides, nitrates of Ca and Mg.
Carbonate hardness = Total hardness or Alkalinity (which ever is less)
Non-carbonate hardness = Total hardness – Alkalinity
Answer:
Physical
Explanation: