chemistry

1. WATER
How much do you know about water ?

2. ABOUT
• It can be used for drinking and as a solvent. The chemical formula
of water is H2O, as it has 2 hydrogen atoms and 1 oxygen atom.
So, the chemical name of water is dihydrogen oxide.
• There are types of water in chemistry we will discuss 3 of
them:-
• Heavy water.
• Hard water.
• Soft water.

3. HEAVY WATER
• Heavy water was first produced in 1932, a few months after the discovery of
deuterium.[7] With the discovery of nuclear fission in late 1938.
• The graphite moderated tried to avoid using either enriched uranium or heavy
water (being cooled with ordinary "light" water instead) which produced the
positive void coefficient that was one of a series of flaws in reactor design leading to
the Chernobyl disaster.
• Heavy water is used in certain types of nuclear reactors, where it acts as a neutron
moderator to slow down neutrons.
• India is one of the world's largest producers of heavy water through its Heavy
Water Board.[68] It exports heavy water to countries including the Republic of
Korea, China, and the United States.

4. FACTS
• Production of pure heavy water by distillation or electrolysis requires a large cascade of stills or
electrolysis chambers and consumes large amounts of power, so the chemical methods are
generally preferred.
•
Experiments with mice, rats, and dogs[45] have shown that a degree of 25% deuteration causes
(sometimes irreversible) sterility, because neither gametes nor zygotes can develop. High
concentrations of heavy water (90%) rapidly kill fish, tadpoles, flatworms, and Drosophila.
• Deuterium-poisoned mammals die of a failure of bone marrow (producing bleeding and
infections).
• Heavy water is normally radioactive and more severely toxic than it actually is. Even if pure
heavy water had been used in the water cooler indefinitely, it is not likely the incident would
have been detected or caused harm,
• The mode of death appears to be the same as that in cytotoxic poisoning .

5. HARD WATER
• The simple definition of water hardness is the amount of dissolved calcium and
magnesium in the water. Hard water is high in dissolved minerals, largely
calcium and magnesium.
• TYPES:-
• Temporary
• Permanent

6. REMOVAL
• PERMANENT HARNESS:-
1. (i) Treatment with washing soda (sodium
carbonate): Washing soda reacts with
soluble calcium and magnesium chlorides
and sulphates in hard water to form
insoluble carbonates
1. (ii) Calgon’s method: Sodium
hexametaphosphate (Na6P6O18),
commercially called ‘calgon’, when added
to hard water,
• TEMPORARY HARDNESS:-
• (i) Boiling: During boiling, the soluble
Mg(HCO3 ) 2 is converted into insoluble
Mg(OH)2.
• (ii) Clark’s method: In this method
calculated amount of lime is added to hard
water.