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Difference from other substance by its unusual properties |
1. Water is Di- polar
The water molecule is formed by the bonding of Oxygen atom with hydrogen atom by covalent bond with bond angle 104.50. In which the Oxygen atom is placed in the vertex and Hydrogen atoms are at the tips. Since Oxygen is highly electro negativity is (3.5). On pouling scale and Hydrogen have the electro negativity (2.5) on pouling scale. The bonded electron pairs will remain more close to the Oxygen atom, which result in the formation of delta positive charge in hydrogen atom and delta negative charge in oxygen atom. This kind of charge formation within a nucleus is called di-pole. The di-polar nature of water becomes the reason for the intermolecular attraction (relatively positive areas attracted relatively negative areas). In addition to the intermolecular attraction of other polar molecules. The feable bridge bond formed between the Hydrogen atoms of one molecule with Oxygen atom of adjacent molecule is called Hydrogen bonding. This Hydrogen bonding makes one molecule connect strongly with other molecule that’s why water is a liquid. And this exceptional character of water makes it very different from any other molecules or compounds.
2. Rare Quality of Water as a Molecule.
May God created lot of things in the Universe, and may each of them have its own speciality. But water is one which nothing can be compare or substitute, as it is the vital force of life. We know life arise only in the place where water is there and life remains only in the places where water is there, water is a force and water is energy. But if this water is contaminated, the life is contaminated. The contamination of life certainly leads to fatel results.
Any material on freezing decreases its volume but water on freezing increases its volume. It is because when it cools to near freezing point, the energy is utalised by the molecules to rearrange to form a structure with that to be in lower density. It may be the reason why solid form of ice float in water. Water reaches its highest density at a temperature of 40C.
Water as a Solvent
Water is a good solvent due to its polarity. This solvent property of water is vital in biology. We know the all Bio- chemical reactions occur with in aqueous solutions (eg: reactions of Cyto plasm and Blood) Due to solvent properties of water, it become a good transport media of biological molecules also when an ionic or polar molecules entered in water it is surrounded by water molecules, due to relatively small size of water molecules it typically allows many water molecules to surround one molecules of solute ( miscle).
The partially negative di-poles of water attract the positively charged components of the solute and viz versa. This is the reason by the most of the electrovalent compounds or ionic compounds are soluble in water. We can see non polar substance like fats; oils does not dissolve in water as they stay together, in water because it is energetically more favourable for the water molecules to hydrogen bond to each other than Van der Wall’s attractions with non- polar molecules.
Cohesion and Surface Tension
Due to the presence of Hydrogen bond water is highly Cohesive in nature. Due to this the surface Tension of water is high. We know the surface Tension of water is how important for us. When a small quantity of water put into a non-soluble surface water state together as a drop. Water occupies the shape of the container is because of this Surface Tension. This property of water is important when water is carried through Xylem up stem in plant. The strong molecular attraction is the reason why it hold the water column together, as prevent tension caused by transpiration pull.
Conductivity
Very interesting think of water is even if it is charged molecule (di-polar) water itself is a insulator. That is does not conduct electricity well. Being a good solvent always it may contain some solute. In that case with some impurities it conducts electricity well.
Reactivity
Chemically water is amphoteric material capable to act as an acid or base. Its PH remains 7(neutral). In some cases water act as an acid in chemical reaction (proton donor) in that case occasionally called as hydroxy acid. And at neutral PH of 7 the concentration of OH- ions is almost equal to that of Hydronium ions (H3O+) or H+ ions. When this equilibrium is disturbed water become either acidic (higher Hydronium ions) or basic (higher hydroxide ions).
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