PAGE 1: WHAT ARE ACIDS?
Welcome to the fascinating world of chemistry! Today, we're going to explore
three fundamental types of compounds: acids, bases, and salts. These
substances are all around us, from the food we eat to the cleaning products
we use.
DEFINING ACIDS
An acid is a substance that increases the concentration of hydrogen ions (H⁺)
when dissolved in water. Think of hydrogen ions as tiny positively charged
particles. When an acid is in water, it releases these H⁺ ions, which are
responsible for many of the characteristic properties of acids.
PROPERTIES OF ACIDS
• Taste: Acids typically have a sour taste (like lemons or vinegar).
• Feel: Concentrated acids can be corrosive and cause burns on the skin.
• Litmus Test: Acids turn blue litmus paper red. Litmus paper is a special
indicator that changes colour in the presence of acids or bases.
• Reaction with Metals: Acids react with many metals to produce
hydrogen gas.
• Neutralization: Acids react with bases in a process called neutralization.
COMMON EXAMPLES OF ACIDS
• Hydrochloric Acid (HCl): Found in our stomach to aid digestion.
• Sulfuric Acid (H₂SO₄): Used in car batteries.
• Acetic Acid (CH₃COOH): The main component of vinegar.
• Citric Acid: Found in citrus fruits like oranges and lemons.
Litmus paper changes colour in the presence of acids and bases.
In summary, acids are compounds that release H⁺ ions in water, leading to
sour tastes, the ability to turn blue litmus paper red, and reactivity with
metals.