ACIDS, BASES AND SALTS

An acid is a substance that donates hydrogen ions (H⁺) when dissolved in water. Acids taste sour and turn blue litmus paper red. Common examples include lemon juice, vinegar, and hydrochloric acid found in your stomach. A base is a substance that accepts hydrogen ions or donates hydroxide ions (OH⁻) in water. Bases taste bitter and feel slippery on your skin. They turn red litmus paper blue. Think of Nigerian examples like lime juice being acidic and soap being basic.

The strength of an acid or base depends on how many ions it releases in water. Strong acids completely ionize, while weak acids partially ionize. When an acid reacts with a base, they neutralize each other, producing salt and water in a process called neutralization.

Acids are sour substances that turn blue litmus paper red, while bases are bitter and turn red litmus paper blue. The main chemical property of acids is that they react with bases to form salt and water—this is called neutralization. Acids also react with metals to produce hydrogen gas, which you can test with a burning splint that goes "pop."

Bases have opposite properties: they're slippery to touch and neutralize acids. Think of lime juice, which is acidic and commonly used in Nigerian kitchens. When you add lime to a bitter substance, the acid neutralizes the bitterness—that's neutralization happening right there in your cooking!

Another key chemical property is that both acids and bases conduct electricity when dissolved in water because they form ions. Strong acids like hydrochloric acid are completely ionized, while weak acids only partially ionize.

Electrolytes are substances that conduct electricity when dissolved in water or melted. Acids, bases and salts are all electrolytes because they break down into charged particles called ions. When you dissolve table salt in water, it separates into sodium and chloride ions that allow electric current to pass through. Similarly, when hydrochloric acid dissolves in water, it splits into hydrogen and chloride ions, making it conduct electricity. Bases like sodium hydroxide also ionize to form ions in solution. Non-electrolytes like sugar don't break into ions, so they cannot conduct electricity even when dissolved. The strength of an electrolyte depends on how much it ionizes. Strong acids like sulphuric acid ionize completely, while weak acids like ethanoic acid only partially ionize. Understanding electrolytes helps explain why some solutions conduct electricity better than others.

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Acids and bases can be sorted into different groups based on their strength and how many hydrogen ions or hydroxide ions they release. Strong acids like hydrochloric acid completely dissolve in water and donate all their hydrogen ions. Weak acids like ethanoic acid (the acid in Nigerian vinegar) only partially dissolve, releasing fewer hydrogen ions. Similarly, strong bases like sodium hydroxide fully dissociate in water, while weak bases like ammonia solution only partially dissociate.

Another way to classify them is by the number of hydrogen or hydroxide ions they can produce. Monobasic acids like hydrochloric acid release one hydrogen ion, while dibasic acids like sulfuric acid release two. This classification matters because it affects how acids and bases react with other substances.

pH is simply a measure of how acidic or basic a substance is. The pH scale runs from 0 to 14, where 7 is neutral (neither acidic nor basic). Numbers below 7 indicate acidity, while numbers above 7 indicate basicity. Pure water has a pH of 7.

Think of lime juice, which you use in Nigerian kitchens – it's acidic with a pH around 2-3. When you add baking soda to neutralize the sourness, you're adding a base that increases the pH. The lower the pH number, the more acidic the substance and the more hydrogen ions it contains. The higher the pH, the more basic it is.

pH is mathematically defined as the negative logarithm of hydrogen ion concentration. Understanding pH helps predict how substances will react with each other – acids and bases neutralize each other to form salts and water.