Properties of Acids and Bases
Acids accept electron pairs, they donate hydrogen protons. Meanwhile, bases donate electrons and accept hydrogen protons. Acids and bases are classified based on their properties as well. The properties comprise pH, taste, texture, reactivity and conductivity.
The name ‘acid’ is derived from the latin word acidus, meaning sour. It should be noted that several acids are sour in taste and have a sharp odor.
pH of Acids and Bases
The pH scale is an indication of how acidic or basic a solution is. It ranges from 0 to 14. While acidic solutions have a pH of less than 7, bases tend to have a pH higher than 7. Solutions that have a pH of 7 like water are considered to be neutral. There are several ways to measure the pH of a solution, but two of the most popular methods are the use of indicators and probes. Probes are touted to be more accurate since the device is placed into the solution and digitally read. We must use our eyes to observe any color change in indicators and compare it to the pH scale. Litmus paper is a type of indicator. While acids turn blue litmus paper red, bases will turn red litmus paper blue.
High concentration of hydrogen protons are present in acidic solutions, on the other hand, basic solutions will have high concentration of hydroxide ions. In a neutralization reaction, acidic and basic solutions combine, cancel each other out. Salts and water are the by-products.
Taste and Texture
You are not supposed to consume or directly touch chemicals!
But still, acids taste tart or sour. They taste like lemon.
Bases tend to taste bitter. (Incase you have tasted a bubble of soap!)
Chemicals are harmful and abrasive for your skin. But in a lab, with precautions, acids and bases can be differentiated by touch. A ‘base’ solution feels soapy or slippery. Acids are rough to touch.
Reaction with Metals
An acid reacts with a metal to produce salt and hydrogen gas. For example, when magnesium reacts with hydrochloric acid, magnesium chloride and hydrogen gas are produced. Bases do not usually react with metals, zinc and aluminum are among the exceptions.
Reactions with Carbonates
Acids react with carbonates producing salt, water and carbon dioxide. To determine whether a solution is acidic or basic, add carbonate solution. In case carbon dioxide is produced, the solution is acidic.
Reaction with Fats/Oils
Bases combine with fats to form glycerol or soap.
Conductivity of Acids and Bases
Strong acids and bases function as strong electrolytes. Since their ions are mobile, electrolytes can conduct electricity in their aqueous states.
An amphoteric compound can react with either an acid or a base. They are mostly metal oxides or hydroxides. While amphoteric compounds react with acids to form a metal salt, they form a polyatomic metallic ion during reaction with a strong base.
Chromium hydroxide, tin hydroxide, and lead hydroxide are few examples of amphoteric compounds.
Certain acids have more than one acidic proton, they are known as polyprotic acids. They have a wide variety of applications. Examples: sulfuric acid or phosphoric acid.