Acids, Bases and Salts

Overview

Acids, bases and salts form a foundational chapter in upper-primary science, bridging everyday experiences (lemon sourness, soap slipperiness) with core chemical concepts. For WB TET Paper II, this topic tests your understanding of characteristic properties, behaviour with indicators, neutralisation reactions and practical applications. Questions typically ask you to identify substances as acidic or basic, predict indicator colour changes, write simple chemical equations for neutralisation, and recall common uses of acids, bases and salts.

Mastery here requires memorising indicator colour charts, understanding the pH scale conceptually, and knowing real-world examples. The topic also connects to environmental science (acid rain, soil pH) and health (antacids, oral hygiene), making it a favourite for application-based questions.

Key Concepts

• **Acids** are substances that release hydrogen ions (H⁺) when dissolved in water. They taste sour, turn blue litmus red and react with metals to produce hydrogen gas.

• **Bases** are substances that release hydroxide ions (OH⁻) in water. They taste bitter, feel soapy/slippery and turn red litmus blue.

• **Alkalis** are bases that dissolve in water. All alkalis are bases, but not all bases are alkalis (e.g., copper hydroxide is a base but not an alkali).