The non-metallic elements are either solids, liquids or gases. Sulphides are formed by nearly all elements except oxygen, fluorine, chlorine, bromine, iodine, neon, argon, krypton, and xenon. The sulphides of metals are solids, and those formed by the heavy metals are insoluble in water. Nitride of hydrogen is ammonia (H3N), phosphide of hydrogen is phosphine (H3P), arsenide of hydrogen is arsine (H3As), and antimony's hydrogen compound is stiline (H3Sb). All these compounds are gaseous.
From this chapter, the student will perceive that binary compounds have a simple structure. No true binary compound can contain more than nine atoms, as in Mn207. Hydroxides are formed by single elements with hydroxyl (HO or OH), and water is both an oxide and hydroxide of hydrogen.
Acids like acetic acid, citric acid, lactic acid, oxalic acid, and tartaric acid are organic acids found in fruits and vegetables. Inorganic acids such as sulphuric acid, nitric acid, hydrochloric acid, and phosphoric acid have corrosive properties and must be handled with caution.
Hydrogen acids (hydrofluoric, hydrochloric, hydrobromic, and hydriodic) are binary compounds of hydrogen and halogens. Hydroxyl acids contain oxygen as well as hydrogen and form salts when combined with bases.
Alkalies like caustic potash, caustic soda, and ammonia have corrosive properties but neutralize acids to form salts. Strong alkalies change the color of red litmus paper to blue.
When an acid and an alkali are mixed in definite proportions, their corrosive properties are neutralized, forming a salt with different taste characteristics.
Bases like metallic hydroxides have the power to neutralize acids and form salts. Most bases are solids; some are liquid or gaseous.
Acids form salts by exchanging hydrogen for metals. Salts contain three elements: basic element, acidic element, and oxygen. Halides formed by hydrogen acids with bases differ structurally from true salts.
Many common substances that look like salts are not salts at all, while others that do not resemble salt are actually salts due to their chemical structure.
The names of salts derive from the acids used in their formation; nitric acid forms nitrates, sulphuric acid forms sulphates, and so on. Salts can be decomposed back into acids and bases through chemical means.
Key Takeaways
- Binary compounds cannot contain more than nine atoms
- Hydroxides are formed by single elements with hydroxyl groups
- Acids and bases neutralize each other to form salts
Practical Tips
- Handle strong acids and alkalies carefully due to their corrosive nature
- Use litmus paper to test for the presence of acids or bases in a solution
Warnings & Risks
- Strong acids and alkalies are dangerous and must be handled with caution
- Do not taste any acid or alkali unless it is highly diluted
Modern Application
While this chapter provides foundational knowledge on chemical compounds, modern safety protocols and equipment have advanced. Understanding the principles of acids, bases, and salts remains crucial for various applications in chemistry and pharmacy.
Frequently Asked Questions
Q: What are some examples of organic acids mentioned in this chapter?
The chapter mentions acetic acid (vinegar), citric acid (lemon juice), lactic acid (sour milk), oxalic acid (pie plant), and tartaric acid (grapes).
Q: How do acids and bases neutralize each other?
When an acid and a base are mixed in definite proportions, their corrosive properties are neutralized, forming a salt with different taste characteristics.
Q: What is the difference between hydroxyl acids and hydrogen acids?
Hydrogen acids (hydrofluoric, hydrochloric, hydrobromic, hydriodic) are binary compounds of hydrogen and halogens. Hydroxyl acids contain oxygen as well as hydrogen.