Acids and Bases By: Mark Vincent F. Abadies Ceferino Kevin A. Tan

What are the physical and chemical behavior of acids and bases? Acids are physically sour, they are soluble in water, they turn blue litmus paper to red, and have a pH value <7. They are mostly electrolytes, and they release H-. They react with reactive metals (above H in Reactivity Series) to form Salt & Hydrogen Gas. They react with Metal Carbonates to form Salt, Carbon Dioxide & Water. And they neutralize bases. Bases are physically bitter in taste, and are slippery.

How do we differentiate an acid from a base? Acids react with metals to form Hydrogen gas. Acids taste sour. Acids frequently feel sticky. Acids are usually gases or liquids. Acids turn Blue litmus paper to Red. Bases taste bitter. Bases feel slippery. Bases turn red litmus paper to blue. Mostly, Bases are solids.

How are the strengths of acids and bases identified? The strengths of acids and bases are identified with the pH scale. When substances measure less than 7 on the pH scale, they are acidic When substances measure more than 7 on the pH scale, they are alkaline, and are therefore bases.

How are acids and bases quantified? Acids and bases are quantified from 0 to 14 on the pH scale. (pH stands for ‘potential of Hydrogen’) The pH scale is logarithmic and runs from 0.0 to 14.0 with 7.0 being neutral. Readings less than 7.0 indicate acidic solutions, while higher readings indicate alkaline or base solutions. Some extreme substances can score lower than 0 or greater than 14, but most fall within the scale.

What are pH indicators? A pH indicator is a halochromic chemical compound that is added in small amounts to a solution so that the pH (acidity or basicity) of the solution can be determined visually. A halochromic material is a material which changes colour when pH changes occur. The term ‘chromic’ is defined as materials that can change colour reversibly with the presence of a factor. In this case, the factor is pH.

What are common applications/uses of acids and bases? The most common use of an acid like HCl, is for cleaning our bathroom, and our kitchen lavatories. It is also used to neutralize bases. The most common use of a base is also for cleaning. Examples are toothpaste, and cleaning products.

Examples of acids and bases