Acids and Alkalis: Strong and Weak Acids

Strong acids and weak acids both give off hydrogen ions (H+) when dissolved in water, but the amount can vary greatly.
Strong acids, like hydrochloric acid, sulfuric acid, and nitric acid, completely ionize in water, meaning every molecule of the acid gives a hydrogen ion. As a result, strong acids have a high concentration of H+ ions.
Weak acids, like ethanoic acid, carbonic acid, and citric acid, only partially ionize when dissolved in water. This means only a fraction of the acid molecules release their hydrogen ions. Consequently, the concentration of H+ ions in a weak acid is lower than in a strong acid.
The pH scale, which runs from 0 (strongly acidic) to 14 (strongly alkaline), measures the concentration of H+ ions in a solution. A lower pH number indicates a higher concentration of H+ ions.
An acid’s strength is not the same as its concentration. Strong or weak only refers to the degree of ionization. However, the concentration (usually measured in moles per liter) shows how much acid is in a certain volume of water.
When an acid reacts with a base, the products are a salt and water. This type of reaction is known as a neutralization reaction.
Hydrogen ions from the acid react with hydroxide ions (OH-) from the base to form water. The remaining particles of the acid and base combine to form a salt.
Indicators, like litmus paper and universal indicator, can be used to test if a solution is acidic or alkaline. Acidic solutions turn blue litmus paper red, while alkaline solutions turn red litmus paper blue.
A universal indicator shows different colors at different pH values, thereby providing a more precise measurement of pH.
Phenolphthalein is another indicator commonly used in acid-base titrations. It is colourless in acidic solutions and turns pink in alkaline solutions.

Safety Points:

Always handle acids and alkalis with care as they can be dangerous.
Always wear safety goggles and suitable gloves when handling acids to protect the eyes and skin.
In case of a spill, neutralize the acid or alkali immediately and clean the area thoroughly.
Always work in a well-ventilated area when dealing with acids and alkalis.