WATER Flashcards
Type of water in textile industry
Water should be soft and free of organic matter. I hard water is used uniform dying is not possible as it decreases the solubility of acidic dyes.
If water contains Fe,Mn it causes uneven dyeing
Type of water in Laundries
they require soft water as hardness increases soap consumption of soaps. Salts of Fe and Mn impart a grey or yellow shade to the fabric
Type of water used in Boilers
they require water of 0 hardness otherwise efficient heat transfer is prevented. It can also lead to the corrosion of boiler material and even explosions
Type of water required in paper industry
it requires water free from
SiO2 (produces cracks in paper)
turbidity (they affect brightness and colour of paper)
alkalinity (consumes alum and increases cost of production)
hardness (they increase ash content of paper)
type of water used in beverages
should not be alkaline as it destroys or modifies the taste as it tends to neutralize fruit acids
type of water used in sugar industry
use of hard water leads to deliquescent sugar
type of water used in cooking
water should be free from dissolved salts producing hardness as it increases fuel consumption
water treatment
process by which all types of undesirable impurities are removed from water and making it fit for domestic or industrial purposes
Sources of water
surface water
underground water
rain water
sea water
Hardness of water
characteristic of water which prevents the lathering of soap
or
soap consumption capacity of water
hard water + soap
when treated with soap it does not produce lather but on the other hand forms insoluble white scum or precipitate which do not produce any detergent action
Hard water vs Soft water
Hard water:
1) does not produce lather with soap solution
2) contains Mg and Ca salts in it
3)cleansing quality of soap is depressed
4) boiling point is elevated
Soft Water:
1) easily forms lather
2)does not contain Mg and Ca salts in it
3)cleansing quality of soap is not depressed
alkalinity
alkalinity is a measure of ability of water to neutralise the acids
Types of alkalinity
Caustic alkalinity (due to OH- and CO3 2- ions)
temporary hardness (due to HCO3 -)
OH- only
CO3 2- only
HCO3 - only
OH- and CO3 2- together
CO3 2- and HCO3 - together
why alkalinity cannot be due to simultaneous presence of OH- CO3 2- and HCO3 - together
OH- and HCO3 - combine together to form CO3 2- ions. thus they cannot exist together
Titration curves for various cases of alkalinity
Book pg 7
why both P and M indicators are required to determine the type and amount of alkalinity in given water sample
book pg 11
Types and extent of alkalinity due to various anions
book pg12
drawbacks of highly alkaline water
caustic embrittlement
deposition of precipitate and sludges in boiler
Temporary hardness
presence of dissolved bicarbonates of Ca, Mg and other heavy metals and carbonates of iron
can be removed via boiling
Temporary hardness is aka
carbonate hardness and alkaline hardness
water for drinking should not be soft
soft water is plumbo-solvent and it attacks lead used in plumbing. solubility of lead in water is diminished in the presence of HCO3 - ions
Permanent hardness
it is due to dissolved chlorides and sulphates of calcium magnesium iron and other heavy metals
removal of permanent hardness
lime-soda process
zeolite process
ion-exchange process
book pg 19
