Water the Neutral Substance
Water is a polar molecule. It is composed of and oxygen. Hydrogen has an electronegativity of 2.2, while oxygen has an electronegativity of 3.5. This means that the shared [?] between hydrogen and oxygen are displaced toward the . As a result, the hydrogen end of the bond has a slight positive charge the oxygen end of the bond has a slight negative charge. These charges are asymmetrically around the water molecule giving it a positive and a negative pole. This a strong attraction between water molecules. The attraction is especially strong because the hydrogens, their electrons drawn toward the oxygen, are essentially a naked protons. As a result, protons from one water molecule form a strong bonds with the oxygens from other molecules. This type of bond is known as a hydrogen bond. It is strong to pull a proton or hydrogen from one water molecule and attach it to oxygen of another. In this way, ions form in water from pure water. The of these ions is low.

Acids, Bases, Salts

The properties of acids and bases caused by the ions they form in water. Due to the presence of ions, solutions of both acids and bases are electrolytes. Acids and bases react with each to form a salt and water. The reaction is a double replacement reaction known neutralization. (Example: HCl + NaOH → NaCl + H2O) Since acid characteristics are caused hydronium ions and base characteristics are caused by hydroxide ions, there are some differences well. Acids increase the hydronium ion concentration of water. Hydronium ion concentration is measured the pH (Power of Hydronium) scale. Acids have a pH below 7. They also sour, the taste of hydronium. Since acids are polar molecules with metallic hydrogen, they with active metals to release hydrogen. This single replacement reaction is responsible for the that acids corrode metals. Acids can be used to clean metals. Bases, on the hand, increase the hydroxide ion concentration of water and reduce the hydronium ion concentration water. As a result, they have a pH above 7. Hydroxide ions taste bitter. don’t react with metals,
but they are not so kind to skin. Bases feel because they dissolve skin. (Dissolved skin makes a great lubricant.) Substances that dissolve skin called caustic. Bases can be used to unclog drains or to make soap. Aqueous of acids and bases look identical. Indicators, substances that react with acids or bases show a definite color change, are used to distinguish between them. See the table the right. Salts are ionic compounds formed during the neutralization reaction between acids and . Salts tend not to have the characteristics of either
acids or bases, because they generally neutral like water. Salts do dissolve in water, however, to form electrolyte solutions.

Acids and Bases in Water

Acids are polar molecules that contain hydrogen as a metal. they are added to water,
they ionize to produce hydronium ions. In pure water, about 1 in every 555,555,555
particles is a hydronium ion [10–7 M]. Addition of to water causes the amount of
hydronium in the water to increase. Bases are compounds that contain hydroxide as a
nonmetal. When they are added to water, they to release hydroxide ions. In pure water,
only about 1 in every 555,555,555 particles a hydroxide ion [10–7 M]. Addition of base to
water causes the amount of in the water to increase. Whenever the hydronium ion
concentration in water increases, the hydronium reacts with hydroxide in water to form
more water and reduce the amount hydroxide present. This is what happens when acids are
added to water. Whenever the ion concentration in water increases, the excess
hydroxide reacts with hydronium in water to more water and reduce the amount of
hydronium present. This is what happens when are added to water.